Cell cultures provide researchers the opportunity to observe cell behavior in response to specific, well-defined environmental cues, leading to insights that enable better engineering design for tissue culture and other biomedical applications. Chemical and electrical stimuli have been successfully applied to cultured cells to approximate aspects of the dynamic conditions experienced in vivo. However, in vitro topographical cues have mostly been limited to static substrates that do not subject cells to the dynamic conditions they experience in vivo when tissue remodels during development and wound healing. Delivering dynamic topographical cues to cultured cells can answer long-standing questions about mechanisms of cell morphology changes. Such capabilities could also facilitate engineering of wound-healing matrices and nerve guidance conduits by promoting migration of cells and providing directional guidance to cellular processes. This dissertation describes the development of approaches for introducing in situ topographical cues to cell cultures and inducing responses such as neurite guidance and cell alignment. Both strategies undertaken in this work make use of multiphoton-promoted photochemistry to print and manipulate three-dimensional microscopic protein hydrogel structures. In one approach, a technique referred to as micro-3D printing, topographical guidance cues are printed in the proximity of cultured cells to guide the growth of cellular processes. By translating a tightly-focused pulsed laser beam through a printing reagent solution flooding cultured cells, features are printed that provide physical guidance to extending neurites from NG108-15 cells, a neuronal model cell type. In another approach, an innovative technique known as micro-3D imprinting is developed for producing micrometer-scale depressions on the surfaces of photoresponsive protein hydrogels. The impact of various experimental parameters on topographical feature dimensions is characterized. Micro-3D imprinting is used to introduce dynamic topographical changes on a cell culture substrate, demonstrating that NIH-3T3 cells, a fibroblast cell model, alter their morphology and alignment in response to the introduction of a grooved surface topography. This set of approaches introduces new tools to the repertoire of cell biologists for exploring the behavior of cells growing in a spatio-temporally dynamic environment, opening possibilities for studies of cellular behavior in conditions that may better reflect environments cells experience in vivo. / text

<p>The general trend in gear industry, today, is an increased focus on gear transmission efficiency. Gear transmission efficiency losses arise from loaded and unloaded gear contacts, seals, lubricant and bearings. One way of minimising the losses is to lower the lubricant viscosity. This will reduce the speed dependent losses. However, the load dependent losses might increase. To avoid this, the ratio between lubricant film thickness and surface roughness must be maintained, which can be fulfilled by producing smoother gear surfaces. As a starting point for this realisation process, the present manufacturing processes, the design tools and the characteristics of the gear flank interface must be further investigated and developed. This must be achieved with an emphasis on economic production.</p><p>This thesis focuses on our understanding of how different gear manufacturing methods —particularly the contribution of the running-in process—affect the surface characteristics, with the view of increasing gearbox efficiency. The thesis consists of a summary and three appended papers.</p><p>Paper A and paper B discuss the relationship between design parameters and real gear wheel surfaces manufactured with different manufacturing methods. The research hypothesis was that the contact area ratio is a descriptive parameter for the contact condition. Paper A deals with the influence of manufacturing method on the initial contact conditions and also serves as a validation of the simulation program used. The emphasis in Paper B is the changes that occur during running-in, and to correlate these changes to design requirements. Paper C approaches the influences of manganese phosphate-coating and lubricants with respect to friction and the risk of scuffing at the initial contact.</p><p>The main conclusions of this thesis are that the contact area ratio presents a descriptive measure of how surface topography influences the contact, seen at both a global (form deviation) and local (roughness) level. The surface topography caused by the manufacturing method has a significant influence on the contact area ratio. This is an important result, since neither national standards nor commercially available gear evaluation programs handle surface topography on the local scale. Shaving was found to have the highest contact area ratio, and should therefore be the best choice if deviations from case hardening could be minimised. It is also confirmed that gear-like surfaces coated with manganese phosphate have a low coefficient of friction, and raise the limiting load for scuffing failure enormously compared to the ground equivalent.</p> / QC 20100518 / KUGG / Sustainable gear transmission realization

The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. When a contact lens is on worn, the tear film covers the contact lens as it would a bare cornea, and is affected by the contact lens material properties. Tear film irregularity can cause both discomfort and vision quality degradation. Under normal conditions, the tear film is less than 10 microns thick and the thickness and topography change in the time between blinks. In order to both better understand the tear film, and to characterize how contact lenses affect tear film behavior, two interferometers were designed and built to separately measure tear film behavior in vitro and in vivo. An in vitro method of characterizing dynamic fluid layers applied to contact lenses mounted on mechanical substrates has been developed using a phase-shifting Twyman- Green interferometer. This interferometer continuously measures light reflected from the surface of the fluid layer, allowing precision analysis of the dynamic fluid layer. Movies showing this fluid layer behavior can be generated. The fluid behavior on the contact lens surface is measured, allowing quantitative analysis beyond what typical contact angle or visual inspection methods provide. The in vivo interferometer is a similar system, with additional modules included to provide capability for human testing. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or videokeratometry and provides better sensitivity and resolution than shearing interferometry methods. The in vitro interferometer system has measured the formation and break up of fluid layers. Different fluid and contact lens material combinations have been used, and significant fluid layer properties have been observed in some cases. This dissertation discusses the design of this interferometer along with analysis methods used. Example measurement results of different contact lens are presented highlighting the capabilities of the instrument. This dissertation also provides the in vivo interferometer design, along with the considerations that must be taken when designing an interferometer for on-eye diagnostics. Discussions include accommodating eye movement, design of null optics for a range of ocular geometries, and laser emission limits for on-eye interferometry in general.

No description available.

The purpose of this thesis is to describe the development of an anatomically based, young adult eye model, which includes a crystalline lens with a gradient refractive index (GRIN). This model will then be used to investigate the effect of laser refractive surgery. The first step in this process involved developing a symmetrical eye model that was found to be a better predictor of empirical longitudinal spherical aberration than any previous model. Myopia was simulated by either a purely axial or refractive technique. While these models were found to be good predictors of the spherical aberration measured in young adults, they did not predict the total amount of high-order aberrations. The techniques used to simulate a single type of myopia caused the myopic models to become anatomically inaccurate. To improve the eye models a biconic surface was used to quantify the anterior corneal shape as a function of myopia. A method to describe the refractive error and biconic shape parameters in Jackson Cross Cylinder terms was implemented to determine correlations. Results indicate that a biconic accurately models the average shape of the anterior corneal surface as a function of myopia. Adopting the biconic model for the anterior corneal surface and adding average misalignments of the ocular components transformed the models from symmetrical to asymmetrical. Refractive error was now simulated by the anatomically accurate changes in both the anterior corneal shape and axial length. The asymmetrical aberrations resulted from the misalignment of the ocular components and provided a good prediction of average empirical aberrations but underestimated the aberrations of individual subjects. Photorefractive keratectomy, a form of laser refractive surgery, was simulated by theoretically calculated and by empirically measured changes in the shape of the anterior corneal surface. Applying the change in anterior corneal shape to the asymmetrical models was used to develop postoperative models. Changes in corneal shape and model aberrations attributed to theoretical calculations do not match empirical observations. The prediction of increased high-order aberrations in postoperative models based on empirically measured changes in the anterior corneal topography was similar to clinical results. Average anatomically based, GRIN eye models have been developed that accurately predict the average aberrations of emmetropic and myopic young adults. These models underestimate the asymmetrical and total high-order aberrations that have been measured in individual subjects but are still useful for investigating the average effects of procedures like refractive surgery.

The visual quality effects from the dynamic behavior of the tear film have been determined through measurements acquired with a high resolution Twyman-Green interferometer. The base shape of the eye has been removed to isolate the aberrations induced by the tear film. The measured tear film was then combined with a typical human eye model to simulate visual performance. Fourier theory has been implemented to calculate the incoherent point spread function, the modulation transfer function, and the subjective quality factor for this system. Analysis software has been developed for ease of automation for large data sets, and outputs movies have been made that display these visual quality metrics alongside the tear film. Post processing software was written to identify and eliminate bad frames. As a whole, this software creates the potential for increased intuition about the connection between blinks, tear film dynamics and visual quality.

Introduction: Most pregnant smokers report abruptly reducing their cigarettes per day (CPD) by ~50% shortly after learning of pregnancy and of making further smaller reductions over the remainder of their pregnancy. Laboratory and naturalistic studies with non-pregnant smokers have found that these types of reductions often lead to changes in smoking topography (i.e., changes in smoking intensity to maintain a desired blood-nicotine level). 19, 20 If pregnant women engage in compensatory smoking, they may expose themselves and their offspring to the same level of toxicants despite reporting reductions in CPD. Methods: Pregnant and non-pregnant female smokers (n = 17 and 91, respectively) participated. At the experimental session, after biochemical confirmation of acute abstinence, all participants smoked one of their usual brand cigarettes ad lib through a Borgwaldt CReSS Desktop Smoking Topography device. Carbon monoxide (CO) and measures of nicotine withdrawal, craving, and reinforcement derived from smoking were also collected. Results: The two groups did not differ on any demographic or smoking characteristics at screening, except nicotine metabolism rate, which as expected, was faster in pregnant smokers. Analyses suggest that none of the smoking topography parameters differed between pregnant and non-pregnant smokers, although pregnant smokers had a significantly smaller CO boost. Both groups reported similar levels of relief of withdrawal and craving after smoking, but other self-report data suggest that pregnant smoker find smoking less reinforcing than non-pregnant smokers. Conclusions: Pregnant smokers do not smoke cigarettes differently as compared to non-pregnant female smokers, but appear to find smoking less reinforcing.

La recherche proposée envisage les modalités de formation des territoires ecclésiastiques entre le Ve et le XIIIe siècledans les diocèses de Rennes, Dol et Alet/Saint-Malo. Le choix centré sur trois diocèses de haute Bretagne se justifie enraison de leur localisation à la rencontre de deux systèmes théorisés d’organisation ecclésiastique entre, d’une part, l’évêché de Rennes de tradition gallo-franque et, d’autre part, les évêchés d’Alet/Saint-Malo et de Dol, lesquels auraient évolué sous l’influence de l’Église dite « celtique » jusqu’au IXe siècle, dans le cadre de l’émigration bretonne à l’ouest de la Vilaine. Dans le premier modèle, les structures ecclésiastiques hériteraient des circonscriptions civiles antiques, tandis que dans l’espace breton, l’Église se définirait davantage en termes communautaires que territoriaux. En se fondant sur les données textuelles et l’archéologie, en particulier des sites funéraires et du bâti religieux, l’objet de l’étude est de montrer que l’Église n’a pas toujours entretenu le même rapport à l’espace, tant en zone bretonne que franque. Ce futseulement au tournant des XIe-XIIe siècles, dans le contexte de la Réforme grégorienne, que l’Église s’imposa comme une institution très temporelle, ayant vocation à prendre en charge le siècle. La création des paroisses, du diocèse et des cadres intermédiaires (archidiaconés et doyennés) s’inscrit alors dans une dynamique unitaire : celle de l’affirmation de l’évêque comme pouvoir autonome, qui, en tant que seul dispensateur du sacré sur terre, exerçait une autorité spirituelle supérieure sur les églises et les clercs relevant de sa juridiction / Our work aimed to understand the formation of ecclesiastical territories of Rennes, Dol and Alet/Saint-Malo dioceses between the fifth and thirteenth centuries. Our focus on these three dioceses of Haute Bretagne is justified by thecrossroads between two theorised systems of ecclesiastical organisation. On the one hand, the Episcopal see of Rennes originated from gallo-frankish tradition and, on the other hand, Episcopal sees of Alet/Saint-Malo and Dol which evolved until ninth century due to the Celtic Church, in the framework of Breton emigration west of the Vilaine. In the first model, ecclesiastical structures were inherited from antique civil districts, contrary to the second model where the Church wasestablished following criteria that were more based on community than territory. Based on textual analysis and archaeology, especially from funeral sites and religious buildings, we intend to show that Church, in the Breton zone as in the Frankish zone, did not always have the same relationship to space. It was only between the eleventh and twelfth centuries, in the context of Gregorian Reform that Church emerged as a temporal institution, dedicated to taking charge of population. The creation of parishes, diocese, archdeaconries and deaneries followed the same dynamics: the affirmation of bishop as an autonomous power, who, as holder of sacredness, have exerted a spiritual authority beyond that exerted by churches or clerics dependents on his jurisdiction

Le polissage mécano-chimique (CMP) en raison de spécifications sévères, telles que l‘aplanissement de la surface à ± 5 nm, est devenu un enjeu crucial pour le développement des nœuds technologiques 14 nm et au-delà. Les méthodes actuelles de caractérisation de la topographie, limitées en termes de taille de surface analysée, évaluent l'efficacité des procédés sur des structures nommées boites de mesure. Ces structures mesurent 100 µm x 50 µm et sont situées entre les circuits intégrés. Elles sont donc non représentatives de la topographie de la puce et, de ce fait, des procédés de métrologie topographique de la puce sont requis. Dans un premier temps, nous montrons que la microscopie interférométrique est capable de caractériser la nano-topographie sur des distances centimétriques avec une résolution latérale micrométrique. La caractérisation par microscopie interférométrique de la nano-topographie induite par les procédés de CMP montre que les méthodes actuelles fournissent des valeurs topographiques non représentatives de la puce. Une méthodologie associée à ce nouveau type de caractérisation est proposée et discutée. Dans un deuxième temps, nous montrons que la diffusion de la lumière permet un contrôle rapide (trois minutes par plaques) et non destructif de variations nanométriques de la topographie de grilles de quelques dizaines de nanomètres de large sur toute la plaque. / Chemical Mechanical Polishing (CMP), because of narrower specifications, as surface planarization at ± 5 nm, is becoming a critical process for the development of the 14 nm technology node and beyond. Habitual topographic characterization techniques, limited in acquisition area, appraise processes efficiency through structures called test boxes. Those structures have a size equal to 100 µm by 50 µm and they are located, in the scribe lines, between the chips. Consequently, they are not representative of the die level topography and die level topographic metrology processes are required. In a first time, we show that interferometric microscopy is able to characterize nano-topography over centimetric distances with micrometric lateral resolution. Interferometric microscopy characterization of CMP processes induced nano-topography demonstrates that usual methods provide non representative die level topography values. A new characterization kind related methodology is proposed and discussed. In a second time, we show that diffused light measurement allows fast (three minutes/wafer) and non-destructive control of gate nano-topography variations for pattern widths of some tenths of nanometer.

Fondée sur une enquête de terrain menée dans des villages jàa du sud ouest du Burkina Faso, cette thèse s'attache à définir l'éligibilité au regard des deux formes socio-spatiales que sont la maison et la route. La maison se présente comme un espace de rivalités, qui ont été provoquées par l'émergence d'un nouveau lieu de pouvoir. Elle témoigne de la création de liens de parenté originaux, mais elle matérialise également l'existence d'une double métamorphose de la virilité dans la société jàa. Cette double métamorphose se caractérise par l'établissement de relations « érotiques » entre les sexes et par la monétarisation de la virilité guerrière. La route, forme socio-spatiale complémentaire et antagonique à la maison, est le lieu à l'origine de ces transformations. Elle incarne le désordre dans la production des hiérarchies politiques : elle figure la propension des candidats aux élections à semer rituellement le chaos lors des meetings politiques et elle est le site depuis lequel s'introduit la déstabilisation du pouvoir. Elle éclaire, en cela, la chute de Blaise Compaoré en octobre 2014. Elle concrétise, plus largement, l'arrivée perçue comme menaçante de migrants Mossi dans les villages et le rôle de l'itinérance dans la révolution des hiérarchies politiques et initiatiques dans la société jàa. La maison et la route composent ainsi une dyade, permettant de décrire, selon une perspective topographique, les transformations des hiérarchies politiques dans une société ouest-africaine. Or, pour concevoir le caractère cadastrable des hiérarchies politiques, il faut situer, au centre de la relation des hommes au territoire, la médiation des croyances et des pratiques religieuses, plutôt que d'envisager une infrastructure économique au pouvoir. / Grounded on a field survey in jàa villages, located in South West Burkina Faso, this thesis aims at defining eligibility from the standing of two socio-spatial forms: the house and the road. The house appears to be a space of rivalries, which have been provoked by the creation of a new centre of power. It highlights the reform of kinship, but it also materializes the double metamorphose of virility in jàa society. This double metamorphose is characterized by the establishment of "erotic" relationships between men and women and by the monetarization of war virility. The road, a complementary and antagonistic socio-spatial form to the house, is the place which gives rise to these changes. It represents the disorder in the political hierarchies production process: it indicates the propensity of local election candidates to ritually create chaos during political meetings and it is the site from which the destabilization of power is introduced. As such, it informs of Blaise Compaoré's fall in October 2014. More broadly, it materializes the intrusion, seen as threatening, of Mossi migrants in villages and the role of roaming in the revolution of political and initiatory hierarchies. Thus, the house and the road compose a dyad, which allows to describe the transformations of political hierarchies in a West African society, following a topographic perspective. Yet, to design the geographical dimension of political hierarchies, it requires placing the mediation of religious beliefs and practices in the centre of the relations between humans and the territory, instead of considering an economical infrastructure of politics.