Search

Examines the role of catalytic residues in enzymatic reaction mechanisms of homologous ketosteroid isomerases (KSI). Properties of KSI active sites; Determination of enzyme crystal structures in free and complex states; Ab initio analysis of the interaction between active sites and reaction intermediates; Length of hydrogen bond in intermediate analogues.

The mobility-degradation factor and the series resistance of cylindrical gate-all-around silicon nanowire field-effect transistors are extracted using the same mobility-degradation model as in the case of planar MOSFETs. The extraction is done by defining an asymptotic voltage as a function of the saturation current measured from devices with various lengths. The extracted mobility-degradation factor is an order of magnitude larger than those of other planar MOSFETs. This result suggests that, while the all-around gate can turn off the electron channel effectively, it creates more interface scattering in the strong inversion condition. The extracted series resistance is mostly due to the crowding of the electron flow along the sidewall of the n+ contact region making an abrupt joint with the nanowire. [ABSTRACT FROM AUTHOR]

HOSO[sub 2] radical is the key intermediate for the oxidation SO[sub 2] to SO[sub 3] by OH radical in the atmosphere. The structural aspects and the energetics of the reaction HOSO[sub 2]+O[sub 2]→SO[sub 3]+HO[sub 2] have been studied using Mo\ller-Plesset (MP2) and density functional (DFT) techniques with 6-31G[sup **] and triple-ζ, quadruple-ζ, and quintuple-ζ quality basis sets including diffuse basis functions. The detailed theoretical analyses have further revealed that this reaction could proceed through the formation of intermediate complexes and an intramolecular proton transfer like transition state. The energetics of these intermediate reactions has been studied in detail. The use of MP2 methods to study such radical mechanisms had some characteristic symmetry-breaking problem with larger basis sets. This unphysical situation with larger basis set MP2 calculations in this hypervalent system has been explained through the interpretation of the relevant energy surface. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]