The mechanism of cytochrome P450(CYP)-catalyzed hydroxylation of primary amines is currently unclear and is relevant to drug metabolism; previous small model calculations have suggested two possible mechanisms: direct N-oxidation and H-abstraction/rebound. We have modeled the N-hydroxylation of (R)-mexiletine in CYP1A2 with hybrid quantum mechanics/molecular mechanics (QM/MM) methods, providing...

Flagellar outer doublet microtubules were solubilized by use of sonication, and the tubulin was reassembled in vitro into single microtubules containing 14 and 15 protofilaments. The tubulin assembly was dependent on both the KCl and tubulin concentrations, exhibiting a critical concentration of 0.72 mg/ml at optimum solvent conditions. Flagellar tubulin was purified by cycles of temperature-de...

Of the impact craters on Earth larger than 20 km in diameter, 10–15% (3 out of 28) are doublets, having been formed by the simultaneous impact of two well-separated projectiles. The most likely scenario for their formation is the impact of well-separated binary asteroids. If a population of binary asteroids is capable of striking the Earth, it should also be able to hit the other terrestrial pl...

contact mechanics is related to the deformation study of solids that meet each other at one or more points. the physical and mathematical formulation of the problem is established upon the mechanics of materials and continuum mechanics and focuses on computations involving bodies with different characteristics in static or dynamic contact. contact mechanics gives essential information for the s...

the aim of the present paper is to sbo» that anti-realism in science, 1vhich has a1;guab/y become more fashionable in recentyears, contrary to tuha: its proponents assert, cannot make use of quantum mechanics and its impressiue achievements as a frump card in justifying its claims. i will argue that scientific anti-realism far from providing scientific communiry with a progressive methodologica...

It is well known that any part of a flagellum has the ability to bend. However, it is not clearly understood how flagella generate successive bending waves spontaneously. Some micromanipulation experiments have suggested that the base of the flagellum is required. By contrast, spontaneous bending waves could be generated in computer simulation work if the microtubules were tied together at one ...

Recently it has been shown that pseudospin symmetry has its origins in a relativistic symmetry of the Dirac Hamiltonian. Using this symmetry we relate single nucleon relativistic magnetic moments of states in a pseudospin doublet to the relativistic magnetic dipole transitions between the states in the doublet, and we relate single nucleon relativistic Gamow Teller transitions within states in ...

We explore the effects of a heavy fermion doublet in a simplified version of the standard electroweak theory. We integrate out the doublet and compute the exact effective energy functional of spatially varying gauge and Higgs fields. We perform a variational search for a local minimum of the effective energy and do not find evidence for a soliton carrying the quantum numbers of the decoupled fe...