Des soucis les plus réels aux affres métaphysiques, Queneau est constamment angoissé par le malheur existentiel et cherchent ainsi l’apaisement spirituel par plusieurs moyens, dont les traditions de l’Orient. Par le biais de René Guénon et des sinologues, il a accès à la pensée chinoise en lisant des classiques et se sent surtout proche des idées du taoïsme. L’intérêt de Queneau à l’orientalisme provient d’une introspection sur les valeurs modernes occidentales. En doutant si l’homme serait capable de distinguer le réel de l’illusion, le vrai du faux, il montre l’attitude sceptique envers le rationalisme. Bien qu’il conçoive ses romans autour du principe de dualité, il met en relief l’interaction et la dépendance mutuelle entre les mondes opposés, tout comme le couple Yin-Yang. Il fait combiner des qualités contradictoires chez un même être, ce qui passe pour une tentative de conciliation des contraires. Les doutes de Queneau s’inscrivent sur trois plans, à savoir la capacité, l’objet et l’outil de connaissances, et présentent bien des analogies avec le scepticisme de Tchouang-tseu. Par l’abdication du désir, Queneau recommande d’abord la simplicité et l’humilité comme recettes de vie. Puis, il préconise l’extinction de l’égo et le détachement spirituel, afin de dépasser des contraintes corporelles et d’apaiser les angoisses existentielles. Il dépeint des personnages heureux à l’image du sage taoïste, qui se caractérisent par l’innocence, l’indifférence et la tranquillité. En suivant la sagesse de non-intervention, on accepte tout dans la vie avec une âme imperturbable et retrouve la béatitude parfaite, incarnée par l’état serein et vital à la naissance. / Raymond Queneau hides his anxious and pessimistic soul under his humorous appearance. To get rid of the anxiety of human being and acquire peaceful mind - true essence of happiness in his viewpoint, he keeps keen interest to orient cultures. Through wide readings, such as the literature of Rene Guénon, many sinologists and the translations of the Taoist classics, Queneau mentions frankly in his diary that he has deeply resonance with ancient China sages.Queneau’s devotion to the orient religion and culture comes from his reflection to Western modern civilization and value. Queneau expresses his confusion of “life is but a dream” with doubts about Logos. Although his productions are filled with “binary pattern”, he emphasizes the interpenetration of opposite sides, which is exactly the same with Chinese Yin-Yang ideology. He deliberately obscures the boundary of opposite sides to combine the seeming inconsistent characteristics into the one unit, which can be regarded as his attempt to reconcile contradiction and shows the bud of relativism. From three aspects of cognition, that is, capacity limitations of cognitive subject, instability of cognitive object and fraudulence of humain language, his novels have lots of similarities with Zhuang-zi’s skepticism. Queneau regards human greed as the source of evil, and proposes the recipe of keeping simple and humble. To break the shackles of time and history, and realize true quiet and spiritual freedom, we need to overcome egoism. Queneau’s characters, like Taoist Sages, are natural and indifferent to the exterior world. They master the way of not-doing, take what comes and be contented. Going back to the original state of infant, they can reach the real inner happiness.

PURPOSE: Normobaric hyperoxia (NBH) has been shown in animal models of experimental retinal detachment (RD) to effectively prevent photoreceptor degeneration. Furthermore, choroidal hyperpermeability has been implicated in the disease pathophysiology. In this study, we studied the effects of 3-hours of 40% FIO2 NBH on photoreceptor morphology and visual acuity in patients with vision loss associated with active central serous chorioretinopathy (CSCR). MATERIALS and METHODS: A total of 8 patients with active unilateral CSCR received at least one 3-hour NBH (40% FIO2) session. Best corrected visual acuity (BCVA) as well as thickness of the central macula, subretinal fluid (SRF), photoreceptor layer (PL), and outer nuclear layer (ONL) were assessed. RESULTS: In patients with unilateral acute CSCR, 3 hours of 40% FIO2 NBH showed a trend towards improved vision, but no statistical differences were obtained for BCVA, CMT, SRF, PL, or ONL. CONCLUSIONS: Administration of 3-hours of NBH did not induce any measurable anatomic changes in the retina nor any significant changes in visual acuity. These results challenge the hypothesis of choroidal hyperpermeability in CSCR and suggest that additional or alternative pathologies contribute to this disease. / 2022-11-29T00:00:00Z

Vitreomacular traction (VMT) is a condition characterized by an incomplete posterior vitreous detachment resulting in traction on the macula and decreased visual acuity. The process of vitreomacular traction can lead to a number of maculopathies including cystoid macular edema, epiretinal membranes, and macular holes. VMT is more common in patients over 40 years of age; however no population-based studies documenting the prevalence of VMT in this age group has been published. Purpose: The current study was undertaken to evaluate the prevalence of vitreomacular traction syndrome in the population aged above 40. Clinical examination does not adequately illustrate the extent of vitreomacular adhesion; therefore, Optical Coherence Tomography (OCT) was used to determine the presence of VMT. High-definition OCT has provided new insight into vitreomacular traction syndrome by allowing for better visualization of the tractional forces at the vitreoretinal interface. This investigation will analyze the vitreomacular interface with regard to VMT in correlation to age through use of the Spectral Domain OCT. Methods: One hundred and thirty-one eyes of 67 patients (36 females/31 males) were examined by optical coherence tomography (OCT). OCT was performed to obtain high-resolution cross-sectional images of the vitreoretinal interface in the posterior fundus. Results: The status of the posterior vitreoretinal interface was evaluated as follows; (1) Intact Vitreous- No posterior vitreous abnormality is depicted on OCT. (2) Vitreomacular adhesion/incomplete PVD- the posterior vitreous is partially attached and can be seen in contact with the macula on OCT. (3) Vitreomacular traction- the posterior vitreous is partially adhered to the inner retina resulting in distortion of the retinal architecture. (4) Complete posterior vitreous detachment, indicating no contact between the vitreous and retina. Conclusion: OCT results found no vitreous abnormality in 39.7% of all eyes; PVD in 6.87% of eyes, VMA in 51.1% of eyes, and VMT in 2.29% of eyes. Age was a significant risk factor to the development of VMT, while gender was not. As age increases, the probability of having VMT increases by 1.2%. Due to the association between vitreomacular traction and a variety of maculopathies, recognition and diagnosis of this entity is crucial. High definition OCT has allowed for outstanding visualization of the vitreomacular interface, which has allowed for a better understanding of this entity.

The vitreous cavity, the largest chamber of the eye, is delimited anteriorly by the lens and posteriorly by the retina and is filled by the vitreous humour. Under normal conditions the vitreous humour has the consistency of a gel, however, typically, with advancing age a disintegration of the gel structure occurs, leading to a vitreous liquefaction. Moreover, after a surgical procedure called vitrectomy the vitreous body may be completely removed and replaced by tamponade fluids. Besides allowing the establishment of an unhindered path of light from the lens to the retina, the vitreous also has important mechanical functions. In particular, it has the role of supporting the retina in contact to the outer layers of the eye, and of acting as a diffusion barrier for molecule transport between the anterior and the posterior segments of the eye. Studying the dynamics of the vitreous induced by eye rotations (saccadic movements) is important in connection of both the above aspects. On the one hand indications exist that the shear stress exerted by the vitreous on the retina may be connected with the occurrence of retinal detachment. On the other hand, if the vitreous motion is intense enough (a situation occurring either when the vitreous is liqueed or when it has been replaced with a uid after vitrectomy), advective transport may be by far more important than diffusion and may have complex characteristics. Advection has indeed been shown to play an important role in the transport phenomena within the vitreous cavity, but, so far, only advection due to the slow overall fluid ux from the anterior to the posterior segments of the eye has been accounted for, while fluid motion due to eye rotations, even if it is generally believed to play an important role, has been invariably disregarded. Some recent contributions have pointed out the importance of accounting for the real vitreous cavity shape in studying uid motion induced by eye rotations. Modelling the vitreous cavity as a deformed sphere, showed that the flow field displays very complex three- dimensional characteristics to which effective fluid mixing is likely to be associated. The purpose of the thesis is to model numerically the motion of the liqueed vitreous within the vitreous cavity induced by different eye movements. Create the model in the Comsol interface, compare the results with theoretical, experimental measurements and do some ow visualizations. Finally show the dependence of the streaming intensity from the amplitude of rotations and the Womersley number .

We illustrate here how a range of fluid and solid mechanics problems relevant to the human eye have been combined in a continuing PhD study. Anterior chamber flow, the solid mechanics of tonometry, the effects of scleral buckle surgery and the mechanics of retinal detachment are all discussed. Finally, a number of other aye problems that are amenable to a theoretical mechanics treatment are proposed.

No description available.

No description available.

Stable suspensions of superparamagnetic cobalt nanoparticles have been prepared in poly(dimethysiloxane) (PDMS) carrier fluids in the presence of poly[dimethylsiloxane-b-(3-cyanopropyl)methylsiloxane-b-dimethylsiloxane] (PDMS-PCPMS-PDMS) triblock copolymers as steric stabilizers. A series of the polysiloxane triblock copolymers with systematically varied molecular weights were prepared via anionic polymerization using LiOH as an initiator. These copolymers formed micelles in toluene or poly(dimethylsiloxane) (PDMS) carrier fluids and served as "nanoreactors" for thermal decomposition of the CO₂(CO)8 precursor. The nitrile groups on the PCPMS central blocks are thought to coordinate onto the particle surface, while the PDMS endblocks protrude into the reaction medium to provide steric stability. The particle size can be controlled by adjusting the cobalt to copolymer ratio. Ordered self-assemblies of these cobalt nanoparticles are observed when the dispersions are cast from toluene. Electron diffraction spectroscopy reveals that the cobalt nanoparticles have fcc crystal structures. TEM shows non-aggregated cobalt nanoparticles with narrow size distributions, which are evenly surrounded with copolymer sheaths. However, some degree of surface oxidation was observed over time, resulting in a decrease in magnetic susceptibility. Novel poly[dimethylsiloxane-b-methyltriethoxysilylsiloxane-b-(3-cyanopropyl) methylsiloxane-b-methyltriethoxysilylsiloxane-b-dimethylsiloxane] (PDMS-PMTEOS-PCPMS-PMTEOS-PDMS) pentablock terpolymers were prepared. These terpolymers could fill the dual role both as steric stabilizers for preparing stable cobalt nanoparticle dispersions and precursors for the particle coating process. Silica films coated on the particles surfaces were employed to prevent the surface oxidation of the nanoparticles. Specific saturation magnetic measurement indicates that coating the nanoparticles with silica thin films can effectively inhibit the oxidation process. / Ph. D.

Air bubbles are a promising means of controlling fouling for a range of applications, particularly delaying fouling in marine environments. This work investigates the mechanism by which the collision of an air bubble with a solid removes adsorbed bacteria. A key feature of the work is that the numbers of bacteria were monitored via video microscopy throughout the collision, so we were able to explore the mechanism of bacteria removal. When a bubble collides with a solid, an air–water interface crosses the solid twice, and we were able to distinguish the effects of the first and second air–water interface. The bacterium Pseudomonas aeruginosa was allowed to adhere to smooth polydimethylsiloxane (PDMS) and then a collision with a bubble was investigated for one of three different approach geometries: perpendicular, parallel, and oscillating parallel to the solid surface. Other factors examined were the speed of the bubble, the duration of bacterial adhesion on the solid surface, and the wettability of the solid. Surface wettability was identified as the most significant factor. When the solid dewets, almost all bacteria were removed from hydrophobic surfaces upon the passage of the first air–liquid interface. In contrast, when a thin liquid film remained between the solid and the bubble (a hydrophilic solid), variable amounts of bacteria remained. Although almost all bacteria were initially removed from hydrophobic solids, many bacteria were redeposited on hydrophobic surfaces upon the passage of the second air–liquid interface, especially when the first and second air–liquid interfaces moved in opposite directions. As described previously, a lower velocity of the bubble allows more time for the thin liquid film to drain, and improved removal efficiency on hydrophilic solids. A rougher solid (8 µm diameter hemispherical protrusions) decreased the detachment efficiency because bacteria and liquid were able to shelter in concavities. Air bubbles are capable of removing bacteria over a range of conditions and are a potentially efficient means of combating biofilm growth for practical applications. / Master of Science / A major problem for equipment submerged in seawater is their eventual coverage in marine organisms including bacteria, barnacles, seaweed, and algae. This work investigates how effectively an air bubble removes bacteria adhered to a submerged solid. Adhered bacteria were observed and counted throughout the interaction of a bubble with a solid. When a bubble collides with a solid and is then removed, the bubble edge passes over the solid twice. The edge of the bubble is referred to as an air–liquid interface. The effects on adhered bacteria removal of the first and second passes of the bubble air–liquid interface were observed. Pseudomonas aeruginosa, a bacterial species common to both marine and medical environments, was allowed to adhere to flat solids made up of the polymer polydimethylsiloxane (PDMS) prior to a collision with an air bubble. The air bubble was collided with the solid in three distinct ways: directly from above, across the solid surface in one direction, and across the solid surface in one direction before being pulled back in the other direction. The speed of the bubble, the amount of time bacteria were adhered to the solid prior to bubble collision, and the extent to which the solid could be wet were all also examined for their effects on adhered bacteria removal. The extent to which a solid surface could be dewetted was identified as the most significant factor. For solids that are easily dewetted, almost all adhered bacteria were removed with the passage of the first air–liquid interface. Many bacteria were then redeposited back onto the solid surface upon the passage of the second air–liquid interface, especially when it moved in a direction opposite to the first. In contrast, for solids that are easily wet by water, variable amounts of bacteria remained after the first air–liquid interface swept across its surface. Slower moving air–liquid interfaces were also shown to be more effective at removing adhered bacteria. Solid surfaces with rough patterning made it more difficult to remove bacteria. Air bubbles can be an effective method to combat adhered bacteria and potentially prevent eventual biological growth on different types of underwater applications.

The biomass from a pilot-scale two-stage (carbon oxidation first stage, ammonia oxidation second stage) fixed-film biological aerated filter (BAF) was divided in three fractions depending on their attachment strength to the media: detached, easily detachable and strongly attached. VSS measurement showed that the detached and easily detachable fractions accounted for 25 to 40% of the biomass in the bed and are present even after backwash. Protein was the major constituent of all fractions of the biomass. The ratio of carbohydrate to protein differed between fractions and between type of biofilms, with a larger value for detached and detachable fractions and a lower value for a largely heterotrophic biofilm, implying a difference in the composition of the biomass matrix that could be related to the attachment state of the biomass. The biomass did not appear to be substrate-limited anywhere in the system, although the specific activity of the biomass was dependent upon the position in the column. Activity of the strongly attached biomass was less than 70% of the total activity, even after backwash. A mass balance on VSS showed that the backwash flushed a mass equivalent to less than 35% to 45% of the detached and detachable fractions, which was less than 15% of the total biomass present in the system. Data also suggested that during backwash, part of the strongly attached biomass was sheared off the media and regenerated the mass of biomass in the detached phase. In conclusion, it can be stated that a non-negligible part of the biomass in a BAF is in a detached state. Actual mechanistic BAF models based solely on biofilm modeling may be overlooking the role of that biomass, especially in the performance recovery of BAF systems after backwash. / Master of Science