This work deals with the study of the influence of metallocene type polypropylene (mPP) molecular weight on isothermal crystallization of its nanocomposites filled with hydrophobic and hydrophilic nanosilica (1 and 2 vol.%). Real amount of nanosilica was determined by thermogravimetry. Isothermal crystallization was performed on differential scanning calorimeter (DSC) at 119–125 °C and observed in-situ under optical polarizing microscope (POM) at 128 °C using hot stage. The increase of mPP crystallinity degree in time was determined on DSC and spherulite type and growth rate was determined using POM. Supramolecular surface structure of the original and isothermally crystallited nanocomposites was observed directly or after chemical etching (mixture of mineral acids with KMnO4) on confocal laser scanning microscope. The crystal structure of mPP was in all tested materials verified by X-ray diffraction.

Introduction : La chronicité de la rhinosinusite, sa résistance aux antibiotiques, et ses exacerbations aiguës laissent croire que les biofilms sont impliqués dans la rhinosinusite chronique. Objectifs : Nous avons évalué la capacité des bactéries Pseudomonas aeruginosa, staphylocoques à coagulase négative et Staphylococcus aureus à former des biofilms par un essai in vitro, et si cette capacité de formation a un lien avec l’évolution de la maladie. Nous avons évalué in vitro l’effet de la moxifloxacine, un antibiotique utilisé dans le traitement de la rhinosinusite chronique sur des biofilms matures de Staphylococcus aureus. Méthodes : Trent et une souches bactériennes ont été isolées de 19 patients atteints de rhinosinusite chronique et qui ont subit au moins une chirurgie endoscopique des sinus. L’évolution de la maladie a été notée comme "bonne" ou "mauvaise" selon l’évaluation du clinicien. La production de biofilm a été évaluée grâce à la coloration au crystal violet. Nous avons évalué la viabilité du biofilm après traitement avec la moxifloxacine. Ces résultats ont été confirmés en microscopie confocale à balayage laser et par la coloration au LIVE/DEAD BacLight. Résultat et Conclusion : Vingt deux des 31 souches ont produit un biofilm. La production d’un biofilm plus importante chez Pseudomonas aeruginosa et Staphylococcus aureus était associée à une mauvaise évolution. Ceci suggère un rôle du biofilm dans la pathogenèse de la rhinosinusite chronique. Le traitement avec la moxifloxacine, à une concentration de 1000X la concentration minimale inhibitrice réduit le nombre des bactéries viables de 2 à 2.5 log. Ces concentrations (100 µg/ml - 200 µg/ml) sont faciles à atteindre dans des solutions topiques. Les résultats de notre étude suggèrent que l’utilisation de concentrations supérieure à la concentration minimale inhibitrice sous forme topique peut ouvrir des voies de recherche sur de nouveaux traitements qui peuvent être bénéfiques pour les patients atteints de forme sévère de rhinosinusite chronique surtout après une chirurgie endoscopique des sinus. / Introduction: The role of biofilms in chronic diseases is increasingly recognized. Chronic rhinosinusitis, with its chronic indolent course, resistance to antibiotics, and acute exacerbations, has an evolution that parallels that of other biofilm-related diseases. Objectives: 1-To develop an in vitro method to assess the biofilm formation capacity. 2- To determine whether biofilm-forming capacity of bacteria demonstrated in chronic rhinosinusitis has an impact on persistence of the disease following endoscopic sinus surgery. 3- To determine the in vitro activity of moxifloxacin against Staphyylococcus aureus in biofilm form. Method: Thirty-one bacterial strains recovered from 19 patients with chronic rhinosinusitis at least one year post-endoscopic sinus surgery. Evolution of disease was assessed by questionnaire and endoscopy as favorable or unfavorable. The bacteria were cultured on a 96-well culture plaque and a semi-quantitative method using crystal violet to quantify biofilm production was used. Confirmation of the effect of the antimicrobial agents on viability was performed with confocal laser microscopy, using a LIVE/DEAD BacLight staining. Results: Twenty-two of 31 samples produced a biofilm thicker or equal to the positive control. Biofilm formation was associated with a poor evolution for Pseudomonas aeruginosa and Staphylococcus aureus, but not for coagulase-negative staphylococci. Biofilm treated with moxifloxacin at 1000X (0.1mg/ml – 0.2 mg/ml) gave a 2 to 2.5 log reduction in number of viable bacteria. Conclusion: We have shown that Crystal violet method is able to detect biofilm formation. There is a correlation between in vitro biofilm production by Pseudomonas aeruginosa and Staphylococcus aureus and unfavorable evolution after endoscopic sinus surgery, suggesting a role for biofilm in chronic rhinosinusitis. Increased concentrations of moxifloxacin, easily attainable in topical solutions have a potential role in the management of biofilm infections.

Untersuchungen zur Kantenfestigkeit von Gläsern zeigen, dass diese in Abhängigkeit des Herstellers und der Kantenbearbeitungsart nach DIN 1249-11 stark variiert. Insbesondere der Bearbeitungsprozess des Schleifens weist eine Vielzahl von Parametern auf, welche die resultierende Oberflächenbeschaffenheit der Glaskante beeinflussen, allerdings noch unzureichend untersucht sind. Eine objektive Erfassung der Oberflächenbeschaffenheit über Kennwerte der Rauheit könnte helfen, Prozessparameter bewertbar zu machen und eine Korrelation zwischen dem Bearbeitungsprozess und der Kantenfestigkeit zu schaffen. Im Rahmen einer ersten Vorstudie wurden Rauheitskennwerte geschliffener und polierter Kantenoberflächen von drei Herstellern mittels konfokalem Laserscanning-Mikroskop ermittelt und hinsichtlich ihrer Eignung zur Bewertung der Bearbeitungsprozesse geprüft. / Roughness examination of processed glass edges under a confocal laser scanning microscope. Findings on the edge strength show that, it varies depending on the manufacturer and the type of edge finishing. In particular the grinding process has a large number of parameters that influence the surface quality of the glass edge, which have not yet been fully investigated. The determination of objective roughness parameters could help to evaluate the grinding processes and further correlate the surface quality with the edge strength. Within the scope of a preliminary study, roughness parameters were calculated for ground and polished glass edges of three manufacturers using a confocal laser scanning microscope. Finally the method was tested regarding to its suitability for a determination of characteristic roughness parameters that could be used to evaluate the grinding processes.

In dieser Doktorarbeit wird die Hypothese geprüft, ob Osteozyten einen direkten Einfluss auf die Knocheneigenschaften in ihrer unmittelbaren Umgebung haben. Der zentrale Experimentieransatz ist dabei die Korrelation der Organisation des Osteozytennetzwerks mit den Mineraleigenschaften des Knochens auf der Submikrometerebene. Es wird gezeigt, dass bereits die anfängliche Ausrichtung der Osteoblasten entscheidend für die Synthese von hoch ausgerichtetem Knochenmaterial ist. Die dabei entstehenden Osteozytennetzwerke sind so organisiert, dass die Osteozyten und ihre Zellfortsätze jeweils einen möglichst kleinen Abstand zum Knochenmineral haben. Deshalb wird vermutet, dass genau diese Netzwerkorganisation mitentscheidend ist, wie gut die Zellen das Mineral in ih-rer Umgebung beeinflussen können. Messungen der Knochenmineraleigenschaften auf Submikrometerebene mit Röntgenkleinwinkelstreuung bestätigen diese Vermutung. Dabei wird deutlich, dass Knochenmaterial in der Nähe der Osteozyten durch andere Mineraleigenschaften geprägt ist. Um zu klären, wie Osteozyten Mineral in ihrer direkten Umgebung verändern können, werden Mechanismen der passiven Mineralherauslösung aus der mineralisierten Oberfläche des Osteozytennetzwerks untersucht. Es wird gezeigt, dass kalziumarme ionische Lösungen unter physiologischen Bedingungen große Mengen von Kalzium-Ionen aus dem Knochen lösen und diese dann durch die Osteozytennetzwerkstrukturen diffundieren können. Zum Abschluss wurde medullärer Knochen von Hühnern als ein Modellsystem für rasanten Knochenumbau untersucht. Dieser spezielle Knochentyp dient den Hennen als labiles Kalziumreservoir und ermöglicht dadurch die tägliche Eierschalenproduktion. Experimente am medullären Knochen-material zeigen insbesondere die Bedeutung von weniger stabilen Mineralstrukturen die benötigt werden um den Knochen an den schnellen, sich wiederholenden Knochenauf- sowie Abbau optimal anzupassen. / This thesis aims to test the hypothesis whether osteocytes have a direct influence on bone material properties in their vicinity. In this regard, the concomitant ana-lysis of osteocyte network organization and bone ultrastructural properties on the submicron level is the central approach to answer this question. In this work, it is shown that already initial cell-cell alignment during the process of bone formation is crucial for the synthesis of highly organized bone. Furthermore it is proposed that the occurrence of highly ordered osteocyte networks visualized with confocal laser scanning microscopy (CLSM) has a strong impact on the ability of osteocytes to directly influence bone material properties. These highly organized networks are another consequence of initial cell-cell alignment and are found to be arranged such as to feature short mineral cell distances. Examination of sub-micron mineral properties with scanning small angle x-ray scattering (sSAXS) shows that bone material in the direct vicinity of osteocytes and their cell proc-esses shows different mineral properties compared to bone further away in the depth of the tissue. Moreover, mechanisms of passive mineral extraction from the mineralized surface of the osteocyte network, due to the treatment with calcium poor ionic solutions, are investigated. It is shown that this chemical process occurring under physiological conditions leads not only to the dissolution of considerable amounts of calcium, but also to efficient diffusion of these ions through the osteocyte network structures. Finally, medullary bone which is intended as a labile calcium source for daily egg shell formation in hens is used as a model system for rapid bone turnover rates. This bone type in particular indicates the importance of uniquely adapted, less stable mineral structures to fit the requirements for rapid bone resorption as well as reformation.

No description available.

No description available.

Sphaerodoridae is a group of benthic marine worms (Annelida) characterized by the presence of spherical tubercles covering their whole surface. They are commonly considered as belonging to Phyllodocida although sistergroup relationships are still far from being understood. Primary homology assessments of their morphological features are lacking, hindering the appraisal of evolutionary relationships between taxa. Therefore, our detailed morphological investigation focuses on different Sphaerodoridae as well as on other members of Phyllodocida using an integrative approach combining scanning electron microscopy (SEM) as well as immunohistochemistry with standard neuronal (anti-5-HT) and muscular (phalloidin-rhodamine) markers and subsequent CLSM analysis of whole mounts and sections. Furthermore, we provide histological (HES) and light microscopical data to shed light on the structures and hypothetical function of sphaerodorid key morphological features. We provide fundamental details into the sphaerodorid morphology supporting a Phyllodocida ancestry of these enigmatic worms. However, the muscular arrangement and the presence of an axial muscular pharynx is similar to conditions observed in other members of the Errantia too. Furthermore, nervous system and muscle staining as well as SEM and histological observations of different types of tubercles indicate a homology of the so called microtubercles, present in the long-bodied sphaerodorids, to the dorsal cirri of other Errantia. The macrotubercles seem to represent a sphaerodorid autapomorphy based on our investigations. Therefore, our results allow comparisons concerning morphological patterns between Sphaerodoridae and other Phyllodocida and constitute a starting point for further comparative investigations to reveal the evolution of the remarkable Sphaerodoridae.

Low cycle fatigue is an important valving parameter of materiale which are exposed random alternate strain during their operation. The alternate strain in that material is caused by temperature fluctuations during operation and outages such as aircraft engines. Tests of low cycle fatigue were performed on samples of superalloy Inconel 738LC at stable room temperature at 23°C. The actual experiment took place at certain intervals, consisting of cycling itself, and observing changes in surface relief by light and electron microscopy. There was observed significant surface relief at an early stage of low cycle fatigue. We compared results of measurement with other different observation methods.

No description available.