Publikationen Institute und Zentren - FH Graubünden

Abstract: An improved size measurement method using spatially modulated illumination (SMI) microscopy enhances subwavelength size determination of fluorescent objects. In this new approach the point spread function of the SMI microscope is reconstructed in each measurement. For this, reference objects with known dye distribution have to be put additionally to the unknown objects on the object slide or on the cover slip. We present data from measurements on fluorescent microspheres with diameters of 140 and 200 nm using an excitation wavelength of 488 nm.

Abstract: Im Frühling 2005 hat Peter Zumthor in Haldenstein sein neues Atelier- und Wohngebäude bezogen. Der Neubau fügt sich in das dörfliche Gefüge Haldensteins ein und verbindet Arbeiten und Wohnen unter einem Dach. Der Bau bildet zusammen mit dem ursprünglichen Atelier und dem ehemaligen Bauernhaus, das Zumthor zuvor selber bewohnte, ein Ensemble, ein eigentliches «Zumthor-Gehöft».

Abstract: Recently developed far field light optical methods are a powerful tool to analyze biological nanostructures and their dynamics, in particular including the interior of three-dimensionally conserved cells. In this article, the recently described method of spatially modulated illumination (SMI) microscopy has been further extended to the online determination of the extension of small, subwavelength sized, fluorescent objects (nanosizing). Using fluorescence excitation with 488 nm, the determination of fluorescent labeled object diameters down to 40 nm corresponding to about 1/12th of the wavelength used for one-photon excitation could be shown. The results of the SMI nanosizing procedure for a detailed, systematic variation of the object diameter are presented together with a fast algorithm for online size evaluation. In addition, we show a direct comparison of the diameter of “colocalization volumes” between SMI nanosizing and conventional confocal laser scanning microscopy.

Abstract: Wave propagation along circular cylindrical structures is important for nondestructive-testing applications and shocks in tubes. To simulate elastic wave propagation phenomena in such structures the governing equations in cylindrical coordinates are solved numerically. To reduce the required amount of computer memory and the computational time, the stress components are eliminated in the equilibrium equations. In the resulting coupled partial differential equations, in which only the three displacement components are involved, the derivatives with respect to spatial coordinates and time are approximated using second order central differences. This leads to the present new approach, which is both accurate and efficient. In order to obtain a stable scheme the displacements must be allocated on a staggered grid. The von Neumann stability analysis is performed and the result is compared with an existing empirical criterion. Mechanical energies are observed in order to validate the finite-difference code. Since no material damping or energy dissipation is taken into account in the equations of motion, the total energy must remain constant over time. Only negligible variations are observed during long-term simulations. Dispersion relations are used to check the physical behavior of the waves calculated with the proposed finite-difference method: Theoretically calculated curves are compared with values obtained by a spectrum estimation method, applied to the results of a simulation.

Abstract: We present the conceptual sociological patterns in this contribution derived from an intensive modelling process with sociologists. The general results in the area of modelling sociological theories, socionics, has been demonstrated: Following the main ideas of C. A. Petri causal dependencies have been modelled. One important sociological outcome of the project is the work of Roman Langer who provided, in parallel to our work in computer science, a thorough integration of sociological theories for the sociological community.

Abstract: Multikulturelle Teams sind oft entweder befangen, weil sie unter den kulturellen Unterschieden der Mitglieder leiden, oder beflügelt, weil sie solche Unterschiede als Chance erkennen und wahrnehmen. Unter welchen Bedingungen multikulturelle Teams ihren Wettbewerbsvorteil nutzen können, war Gegenstand eines Forschungs- und Entwicklungsprojektes der Fachhochschulen von Winterthur und Chur in Kooperation mit den Unternehmen Sunrise, Winterthur Versicherungen, Weidmann und Würth Holding. Das Projekt wurde von der Kommission für Technologie und Innovation KTI, der Förderagentur für Innovation des Bundesamts für Berufsbildung und Technologie, mitfinanziert. Multikulturalität birgt grosse Chancen. Wenn diese genutzt werden, zeichnen sich international zusammengesetzte Teams durch ein hohes Mass an Kreativität, Flexibilität und Sensibilität aus. Allein durch ihre Zusammensetzung sind sie in der Lage, eine grössere Zahl von Alternativen und Ideen zu generieren als kulturell homogene Teams, da die Teammitglieder unterschiedliche Perspektiven, Problemlösungsansätze und Erfahrungen mitbringen. Daneben unterliegen solche Teams weniger der Gefahr des Gruppendenkens, das oft allzu rasch zu altbekannten Lösungen führt.

Abstract: A method for the detection of defects in cylindrical structures and the determination of their positions and orientations is presented in this paper. The scattered field, which is generated by the interaction of excited guided waves with a defect, is evaluated with an approach named time reverse numerical simulation method (TRNS). Since the excited waves and the scattered field propagate along the sample, the time-consuming scanning of the whole tube can be eliminated. The scattered displacement field is measured in three dimensions over time with a laser vibrometer at different locations distributed equally around the circumference at a fixed axial coordinate far away from the defect. Instead of analyzing the complicated time signals directly, they are played back in time. If the recorded displacement histories of the scattered field are reversed in time and played back in an identical structure, the waves travel back the same path and interfere to a maximum at their origin. The result is an amplitude increase at the position of the defect where the scattered field was generated. Instead of playing back the recorded time signals in an experiment, this step is replaced by a numerical simulation. Only this enables the visualization and detection of the amplitude increase. As long as the simulation is of high accuracy, the position of the maximum interference corresponds exactly to the location of the defect in the experiment, although no defect is implemented in the simulation.

Abstract: Spatially modulated illumination fluorescence microscopy can in theory measure the sizes of objects with a diameter ranging between 10 and 200 nm and has allowed accurate size measurement of subresolution fluorescent beads ( approximately 40-100 nm). Biological structures in this size range have so far been measured by electron microscopy. Here, we have labeled sites containing the active, hyperphosphorylated form of RNA polymerase II in the nucleus of HeLa cells by using the antibody H5. The spatially modulated illumination-microscope was compared with confocal laser scanning and electron microscopes and found to be suitable for measuring the size of cellular nanostructures in a biological setting. The hyperphosphorylated form of polymerase II was found in structures with a diameter of approximately 70 nm, well below the 200-nm resolution limit of standard fluorescence microscopes.

Abstract: Die diesjährige 9. Internationale Architekturbiennale in Venedig wird vom Schweizer Kunsthistoriker und ehemaligen Professor an der ETH Zürich und der Accademia di Mendriso Kurt W. Forster geleitet. Er formuliert mit dem Motto «Metamorph» die These des Beginns einer neuen Ära der Architektur. Die eindrückliche Ausstellung zeigt ungewollt aber auch Grenzen dieser Entwicklung.