We estimate the total ee → t̃t̃ cross section near threshold for a Coulombic potential and compare it to the Born approximation. The effect of the beam energy spread for present and future ee colliders is discussed. ∗[email protected]

The singular part of Borel transform of a QCD amplitude near the infrared renormalon can be expanded in terms of higher order Wilson coefficients of the operators associated with the renormalon. In this paper we observe that this expansion gives nontrivial constraints on the Borel amplitude that can be used to improve the accuracy of the ordinary perturbative expansion of the Borel amplitude. I...

Pentavalent organo-vanadates have been used extensively to mimic the transition state of phosphoryl group transfer reactions. Here, decavanadate (V(10)O(28)6-) is shown to be an inhibitor of catalysis by bovine pancreatic ribonuclease A (RNase A). Isothermal titration calorimetry shows that the Kd for the RNase A decavanadate complex is 1.4 microM. This value is consistent with kinetic measurem...

Recent experiments show that membrane ATPases are capable of absorbing free energy from an applied oscillating electric field and converting it to chemical bond energy of ATP or chemical potential energy of concentration gradients. Presumably these enzymes would also respond to endogenous transmembrane electric fields of similar intensity and waveform. A mechanism is proposed in which energy co...

Although the extreme miniaturization of components in integrated circuits and biochemical chips has driven the development of various nanofabrication technologies, the 3D fabrication of nanoscale objects is still in its infancy. Here we propose a novel method to fabricate a free-standing nanowall by the precise, repetitive deposition of electrospun polymer nanofibers. We show that the electrifi...

We studied codoping effects in silicon using first-principles calculations, with particular attention to charge compensation, Coulomb interactions, and strain compensation. We find that for B-doped systems, As or Sb counter doping reduces the maximum hole concentration, but that due to strong binding of multiple P atoms, Ga or In counter doping can increase electron density in heavily P-doped m...

Institute for Condensed Matter Physics, Natl. Acad. Sci. Ukr. 1 Svientsitskii Str., UA-79011 Lviv, Ukraine (Received June 21, 2001) In the limit of infinite spatial dimensions a thermodynamically consistent theory of the strongly correlated electron systems, which is valid for arbitrary value of the Coulombic interaction (U < ∞), is built. For the Hubbard model the total auxiliary single-site p...

A nanoscale coating of a Si layer on the pore walls of SnO(2) nanotubes (Si-coated SnO(2)) leads to very good electrochemical performance in coulombic efficiency, rate capability and capacity retention compared with untreated SnO(2) nanotubes.