ABSTRACT
We found monochromatic electron photoemission from large-area self-assembled monolayers of a functionalized diamondoid, [121]tetramantane-6-thiol. Photoelectron spectra of the diamondoid monolayers exhibited a peak at the low-kinetic energy threshold; up to 68% of all emitted electrons were emitted within this single energy peak. The intensity of the emission peak is indicative of diamondoids being negative electron affinity materials. With an energy distribution width of less than 0.5 electron volts, this source of monochromatic electrons may find application in technologies such as electron microscopy, electron beam lithography, and field-emission flat-panel displays.
ABSTRACT
An anaerobic thermophilic bacterium Thermoanaerobacter ethanolicus 39E (Clostridium thermohydrosulfuricum 39E) gene library was constructed in E. coli. Recombinant plasmid (pUT50) containing the thermostable beta-galactosidase was isolated by direct selection of clones for enzyme activity using 5-bromo-4-chloro-3-indolyl-D-galactopyranoside (X-gal) and mapping procedures were carried out. The beta-galactosidase was purified from cell extracts of E. coli. Physicochemical characteristics of the recombinant beta-galactosidase were determined. The enzyme has two optimum pH values: 5.3 and 6.0, the temperature optimum is 75-80 degrees C. The molecular weight of beta-galactosidase was determined by PAG electrophoresis: about 83 kDa.
