Photoemission electron microscopy as a tool for the investigation of optical near fields.

Photoemission electron microscopy was used to image the electrons photoemitted from specially tailored Ag nanoparticles deposited on a Si substrate (with its native oxide SiO(x)). Photoemission was induced by illumination with a Hg UV lamp (photon energy cutoff homega(UV) = 5.0 eV, wavelength lambda(UV) = 250 nm) and with a Ti:sapphire femtosecond laser (homega(l) = 3.1 eV, lambda(l) = 400 nm, pulse width below 200 fs), respectively. While homogeneous photoelectron emission from the metal is observed upon illumination at energies above the silver plasmon frequency, at lower photon energies the emission is localized at tips of the structure. This is interpreted as a signature of the local electrical field therefore providing a tool to map the optical near field with the resolution of emission electron microscopy.

Improved DNA typing of human urine by adding EDTA.

The effect of different EDTA concentrations on the DNA content of urine samples was examined and compared to untreated urine at various storage temperatures and times. The results indicate that adding EDTA increases the DNA stability for long time storage especially at low temperatures.

Additional primer sets for an amelogenin gene PCR-based DNA-sex test.

When aligning the human amelogenin X (AmelX)-gene with the human amelogenin Y (AmelY)-gene, 19 regions of absolute homology ranging in size from 22 to 80 bp, 5 deletions located on AmelX from 1 to 6 bp and 5 deletions 1-183 bp long located on AmelY can be observed. The regions of absolute homology are used to design primer sets which span deletions of the X- and/or Y-chromosome. The PCR products generated on the X- and Y-homologues differ in size. New regions of deletions and newly designed primers are described to facilitate the integration of the amelogenin sex test into multiplex PCR reactions.