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Messengers from Space
Oct. 10, 2013

Messengers from Space

The macro- and microstructure of iron meteorites provide valuable insights into both the inner structure of our planet and the history of our solar system. High speed collision events in the asteroid belt send the meteorites careening toward Earth. The collisions produce unique deformation microstructures. With cooling rates on the scale of a few degrees per million years, iron meteorites can consist of crystal sizes on the order of meters prior to the collision events. These extremely slow cooling rates result in phase transformations occurring at conditions near thermodynamic equilibrium. Preserving meteorite fragments is important for future studies of phase transformations, material behavior at high strain rates, and the origin of the universe.
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In Situ Straining Analysis with ACOM-TEM
Oct. 05, 2013

In Situ Straining Analysis with ACOM-TEM

The combination of ACOM-TEM with in situ straining inside a TEM enables direct imaging of the local crystal orientation at the nanoscale during straining of nanocrystalline metals and thus various deformation processes such as grain growth, twinning/detwinning and grain rotation can be distinguished in real space. A quantitative analysis of the crystal orientation changes observed by this new approach was used to study the deformation processes in nanocrystalline gold [1].
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Exploring Teeth by Analytical (S)TEM
Sep. 23, 2013

Exploring Teeth by Analytical (S)TEM

Mineralized human dental tissues were studied by advanced analytical transmission electron microscopy (TEM) techniques. The Ca/P and Mg/P at % ratios were determined employing energy dispersive X-ray spectroscopy (EDX) measurements. Significantly lower Ca/P and higher Mg/P at % ratios were measured in peritubular dentine compared to intertubular dentine, suggesting the incorporation of Mg in the hydroxylapatite lattice by substituting Ca. Improvement of TEM sample preparation is demonstrated. more
A New Type of Laser Diode
Sep. 06, 2013

A New Type of Laser Diode

Exciton-polaritons are bosonic quasi particles which mix the properties of excitons and photons [1]. They can undergo a dynamic phase transition, sharing many similarities with Bose-Einstein condensation of ultra-cold atoms. However, due to the light effective mass of polaritons, this transition can take place at much higher temperatures, even up to 300 K in large bandgap semiconductors [2]. When this transition occurs, a macroscopic number of particles populate a common energy state. The photons, which spontaneously leak out of the microcavity, adopt the monochromatic and coherent nature of the polaritons. To date, the effects of polariton condensation and lasing have only been observed in various optically pumped systems [2-5], whereas the clear demonstration of polariton lasing under electrical pumping, which represents a crucial step towards most applications, has been obsolete. more
Nanoflight SEM Movies
Aug. 30, 2013

Nanoflight SEM Movies

The scientific community and with it, every researcher, should be committed to sharing the aesthetics of the microworld, with as many people as possible. In the past it was mostly still shots of the specimen that were available. We thought it would be worth it to bring movement, color and lighting effects into the microworld and so developed a modular software called "nanoflight.creator" [1] with the goal of taking control of parameters like specimen movement, detector values, focus and colors of each detector channel in the Scanning Electron Microscope (SEM).
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Carbon Nanotube Hybridization with Ceramic Micro-Particles
Aug. 26, 2013

Carbon Nanotube Hybridization with Ceramic Micro-Particles

Owing to their unique anisotropic structure and their extraordinary properties, carbon nanotubes (CNTs) have spurred great interest in a wide range of application, and more particularly in materials science where the CNT hybridizations with other materials offer significant advantages. CNTs grown on alumina micro-beads and silicon carbide micro-platelets are among the most promising multi-scale combinations due to their outstanding thermal, electrical and mechanical properties. By simply adjusting the synthesis parameters, one can significantly affect the final structure and thus the properties of the hybrids, opening up a large area to explore. more
Combined Holographic Optical Trapping and Imaging
Aug. 07, 2013

Combined Holographic Optical Trapping and Imaging

We combined holographic optical tweezers (HOT) with self-interference digital holographic microscopy (DHM). HOT allow flexible three-dimensional contactless moving of particles inside cells and positioning of bacteria on host cells while self-interference DHM provides simplified multi-focus quantitative phase imaging and 3D object tracking. Our results demonstrate novel ways for the analysis of the intracellular morphology and modeling of infection scenarios at single cell scale. more
Stem Cell Imaging in Living Animals
Aug. 07, 2013

Stem Cell Imaging in Living Animals

Monitoring stem cells in their natural physiological environment is crucial to understanding stem cell ­differentiation and the generation of tissue. We applied high-resolution 3D multiphoton tomography in order to non-invasively visualize the stem cells of hair follicles. Single nestin GFP-expressing stem cells were tracked for up to five hours in living transgenic mice. The microenvironment was monitored by two-photon autofluorescence and second harmonic generation.
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