Mar. 31, 2010
Organic and mineral samples, containing light elements like oxygen, nitrogen or beryllium have been analyzed using an attachable X-ray optic with an SDD in SEM. Compared to the measurements without the additional optic, there is a significant increase of the detection sensitivity for X-rays in the energy range below 1 keV. In contrast the spectrum above 1 keV is not affected. The optic can provide similar intensities for low and high energy X-ray lines even at high accelerating voltage.
Introduction moreMar. 24, 2010
We have shown that 50 nm details can be distinguished in x-ray images using a compact laboratory set-up. A novel emitter design inside the x-ray source produces a very small, stable focal spot and prevents diffraction limiting effects. Due to unlimited depth of focus, the source doesn't impose a limit on the specimen size that can be reconstructed by 3D x-ray nano-tomography.
Introduction moreFeb. 22, 2010
Fully understanding the functionality and the complexity of the human central nervous system remains as one of the major open questions in modern science. The Drosophila neuromuscular junction (NMJ) is a widely used and acknowledged model for the analysis of synapse structure and assembly. When considering the size of a Drosophila NMJ synapse of about 500 nm in diameter it appears logical that in order to visualize its spatial architecture the resolution of image acquisition methods needs to be accordingly high. moreFeb. 15, 2010
The view of a tumor as an aberrant tissue whose growth and differentiation is sustained by cancer stem cells is now largely accepted for a wide variety of cancer diseases. Cancer stem cells, as their physiological counterparts, possess the ability to control their fate by maintaining themselves in a quiescent and undifferentiated state or self-renewing to geometrically expand their number. moreJan. 25, 2010
Semiconductor quantum dots are light-emitting nanocrystals (2-10 nm) that straddle the border between condensed matter and atomic physics. In a quantum dot, all three spatial dimensions of the crystal are limited to less than the exciton radius of the material such that discrete energy levels arise due to quantum confinement effects and the spacing of which can be controlled by manipulation of crystal size. moreJan. 04, 2010
Morphological characterisation of embryonic stem cells is important in many ways. In culture, the morphology indicates the status of the cells, e.g., undifferentiated or differentiated, and also provides clues about the general health and condition of the cells, e.g, apoptotic, necrotic or mycoplasma contaminated. While there are a vast range of studies characterising stem cell markers by light microscopy, there is limited information about the fine structure of hES cells and colonies by electron microscopy. moreDec. 30, 2009
Synthetic proteo-nucleic structures (PDNA) encompassing a ss-DNA sequence covalently attached to a cytochrome b5-derived protein domain through a synthetic linker were designed. PDNAs can bind to natural or supported membranes through an histidine-tag-nickel-NTA modified phospholipids. Alternatively the structures can be attached, while keeping free lateral diffusion capabilities, by interaction of the protein his-tag with a substrate supported field of nickel ions. moreDec. 29, 2009
The propulsion of the leading edge of neuronal lamellipodia is a complex process in which the polymerization of actin filaments towards the cell membrane is a major component [1,2]. This process is at the origin of force generation in neurons. By using optical tweezers, we have characterized the dynamics by which lamellipodia of Dorsal Root Ganglia neurons exerted force on encountered obstacles such as silica beads. more