0000000000609128
AUTHOR
H. Haas
Protein interactions with ordered lipid films: Specific and unspecific binding
Pressure dependent arrangement of a protein in two-dimensional crystals specifically bound to a monolayer
Abstract The arrangement of streptavidin bound to a biotinylated monolayer of a polymeric amphiphile at the air-water interface is studied as a function of lateral pressure or ligand density. Closely packed domains are observed by fluorescence microscopy. The arrangement of the protein in these domains is sensitively detected by X-ray reflectivity and an especially thorough data analysis yields the following: the distance of the protein from the air-monolayer interface varies with lateral pressure by 10 A; the interfaces involving the protein are much rougher than expected due to capillary waves; the electron density of the protein layer increases considerably on compression, which can be u…
Observation of two-dimensional exciton-phonon quasibound states
We demonstrate the existence of robust exciton-phonon quasibound states (EPQBS) in a two-dimensional semiconductor system, resulting from the binding of the ${e}_{1}{h}_{1}$ and ${e}_{1}{h}_{2}$ heavy-hole quantum-well excitons with an LO phonon. We show that increasing quantum confinement drastically weakens these two-dimensional EPQBS. A theoretical model including phonon confinement accounts qualitatively for our results.
The new CERN-ISOLDE on-line mass-separator facility at the PS-Booster
The ISOLDE on-line isotope separators have been operated since 1967 at the CERN-SC. This 600 MeV proton synchro-cyclotron had to be shut down in December 1990 after 33 years of service and it was decided to move ISOLDE to a new experimental area. The new on-line mass-separator facility is now under construction at the CERN PS-Booster. This accelerator provides an average current of about 2-mu-A of 1 GeV protons in very short high intensity pulses at low repetition rate. The beam can hit either one of the two target stations, the general purpose separator (GPS), a reconstructed ISOLDE-2 type machine (which can deliver beams simultaneously into three beam lines), and the high resolution separ…