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Biophysik / Master (Einschreibung bis SoSe 2012) - News

[Studierende Physik] Einladung zum Physikalischen Kolloquium 02.05.2016 ( 28.04.16 )
Per E-Mail eingestellt von reimann@physik.uni-bielefeld.de:

Liebe Studierende der Physik,

hiermit lade ich Sie recht herzlich zum Physikalischen Kolloquium ein:

Professor Robert Ros, Department of Physics and Center for Biological Physics, Arizona State University

Force measurements for the quantification of molecular interactions, cell adhesion and cell mechanics

02.05.2016, 16:15, Hoersaal 6

Forces and mechanical properties play a central role in many biological processes covering a huge range of length and time scales: from the movement of whole organisms over the adhesion, migration, proliferation of cells, down to the mechanics and interactions of single molecules. For example, cells are able to sense external forces (mechanosensing), translate these mechanical forces into biochemical signals (mechanotransduction) and react to these signals (mechanoresponse). Mechanics also plays an important role on the level of single biomolecules. For example, forces act between ligands and receptors, forces induce conformational changes in biomolecules, and the mechanical properties of biomolecules are often related to their function.
In this talk, I will first focus on recent work in my lab related to mechanical interactions between cells and the extracellular matrix (ECM) critical to the metastasis of cancer cells. To assess the mechanical interplay between the cells and ECM during invasion, we combined confocal fluorescence microscopy and atomic force microscopy (AFM) indentation to determine the Young’s moduli of individual embedded cells and the pericellular matrix using novel analysis methods for heterogeneous samples. In the second part of my talk, I will discuss how physical properties of fibrinogen matrices control the adhesion of blood cells. The adsorption of fibrinogen on fibrin clots and other surfaces strongly reduces integrin-mediated adhesion of platelets and leukocytes with implications for the surface-mediated control of thrombus growth and blood compatibility of biomaterials. We applied AFM based force spectroscopy techniques combined with optical microscopy to quantify the adhesive properties of fibrinogen matrixes on the single cell level and studied the mechanism behind the transformation of highly adhesive to non-adhesive surfaces.

Viele Gruesse,

Peter Reimann

http://www2.physik.uni-bielefeld.de/veranstaltungen.html

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Prof. Dr. Peter Reimann
Universitaet Bielefeld
Fakultaet fuer Physik
Postfach 10 01 31
33501 Bielefeld
Tel.: +49-521-106-6206
Fax: +49-521-106-6455
email: reimann@physik.uni-bielefeld.de
web: http://www2.physik.uni-bielefeld.de/condmat_reimann.html
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Information zum Mailverteiler: Alle Studierenden der Fakultaet fuer Physik
[Studierende Physik] Einladung zum Physikalischen Kolloquium 25.04.2016 ( 21.04.16 )
Per E-Mail eingestellt von reimann@physik.uni-bielefeld.de:

Liebe Studierende der Physik,

hiermit lade ich Sie recht herzlich zum Physikalischen Kolloquium ein:

Prof. Dr. Thomas Klinger, MPI für Plasmaphysik and Ernst-Moritz-Arndt-University Greifswald

The long way to steady state fusion plasmas - the superconducting stellarator device Wendelstein 7-X

25.04.2016, 16:15, Hoersaal 6

The stable generation of high temperature Hydrogen plasmas (ion and electron temperature in the range 10-20 keV) is the basis for the use of nuclear fusion to generate heat and thereby electric power. The most promising path is to use strong, toroidal, twisted magnetic fields to confine the electrically charged plasma particles in order to avoid heat losses to the cold, solid wall elements. Two magnetic confinement concepts have been proven to be most suitable: (a) the tokamak and (b) the stellarator. The stellarator creates the magnetic field by external coils only, the tokamak by combining the externally created field with the magnetic field generated by a strong current in the plasma. “Wendelstein 7-X” is the name of a large superconducting stellarator that goes into operation after 15 years of construction. With 30 m^3 plasma volume, 3 T magnetic field on axis, and 10 MW micro wave heating power, Hydrogen plasmas are generated that allow one to establish a scientific basis for the extrapolation to a future fusion power plant. It is a unique feature of Wendelstein 7-X to be able to operate high-power Hydrogen plasmas under steady-state conditions, more specifically for 1800 s (note that the world standard is now in the 10 s ballpark). This talk provides a review of the principles of nuclear fusion and discusses the key physics subjects of optimized stellarators. The sometimes adventurous undertaking to construct such a first-of-a-kind device is summarized as well. We finish with an outlook towards the fusion power station and address the most important remaining issues to be addressed in the framework of the world-wide fusion research endeavor.

Viele Gruesse,
Peter Reimann

http://www2.physik.uni-bielefeld.de/veranstaltungen.html

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Prof. Dr. Peter Reimann
Universitaet Bielefeld
Fakultaet fuer Physik
Postfach 10 01 31
33501 Bielefeld
Tel.: +49-521-106-6206
Fax: +49-521-106-6455
email: reimann@physik.uni-bielefeld.de
web: http://www2.physik.uni-bielefeld.de/condmat_reimann.html
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Information zum Mailverteiler: Alle Studierenden der Fakultaet fuer Physik
[Studierende Physik] Einladung zum Physikalischen Kolloquium 11.04.2016 ( 07.04.16 )
Per E-Mail eingestellt von reimann@physik.uni-bielefeld.de:

Liebe Studierende der Physik,

hiermit lade ich Sie recht herzlich zum Physikalischen Kolloquium ein:

Prof. Dr. Frank Scheffold, Universität Fribourg

Hyperuniformity and the packing of soft spheres: from dense emulsions to photonic materials design

11.04.2016, 16:15, Hoersaal 6

The random packing of spherical objects has fascinated researchers for centuries. When hard or soft spheres are quenched above a volume fraction of about sixty percent, a supercooled fluid of spheres enters an amorphous solid phase. The state of matter of this phase is peculiar since it has both fluid- and solid-like attributes: it has a liquid-like structure, yet mechanically responds to an applied stress as a solid. This called ‘glass’ and \"jamming” phenomenon is not only of fundamental interest but also of prime importance in materials science since it governs the elasticity and flow of many soft materials such as emulsions, particle dispersions, polymeric thickeners as well as granular materials (sand, powders, etc.).
After a general introduction I will discuss experiments and concepts derived from jammed assemblies of microscale hard and soft spheres. In the first set of studies we investigate deformable particles suspended in water either consisting of oil droplets or microgel-particles that are driven into a glassy and jammed state. To study the swelling behavior and the compression of individual microgel particles on the nanoscale we have implemented dSTORM superresolution microscopy with a 30nm optical resolution. We then probe the global 3D structure and translational motion of particle positions with scanning confocal microscopy.
In a second set of experiments we used jammed assemblies of spheres as templates for photonic structures. We follow a protocol based on mapping the hyperuniform point coordinates of the spheres into tessellations for disordered photonic materials design. Using direct laser writing in a polymer photoresist we succeeded in fabricating such structures with features on the submicron scale.

Viele Gruesse,

Peter Reimann

http://www2.physik.uni-bielefeld.de/veranstaltungen.html

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Prof. Dr. Peter Reimann
Universitaet Bielefeld
Fakultaet fuer Physik
Postfach 10 01 31
33501 Bielefeld
Tel.: +49-521-106-6206
Fax: +49-521-106-6455
email: reimann@physik.uni-bielefeld.de
web: http://www2.physik.uni-bielefeld.de/condmat_reimann.html
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Information zum Mailverteiler: Alle Studierenden der Fakultaet fuer Physik