in this paper, the electronic eigenstates and energy spectra of single and two-interacting electrons confined in a concentric double quantum rings with a perpendicular magnetic field in the presence of         on-center donor and acceptor impurities are calculated using the exact diagonalization method. for a single electron case, the binding energy of on-center donor and acceptor impurities ar...

A range of highly substituted tetrahydropyrans have been prepared by reaction of a donor-acceptor cyclobutane, where the donor is a metal-alkyne complex, with an aldehyde under Lewis acid conditions.

Acid-base catalyzed glycosyl donor and then glycosyl acceptor activation with phenylboron difluoride or diphenylboron fluoride permits hydrogen bond mediated intramolecular S(N)2-type glycosidation in generally high anomeric selectivity.

A new electrochemical sensor was demonstrated for selective sensing of 3,4-dihydroxyphenylacetic acid (DOPAC) through a non-oxidative mechanism by using single-walled carbon nanotubes (SWNTs) as the electronic transducer and a synthetic cyclophane electron acceptor as the recognition element.

Three-dimensional structures are not available for polysaccharide synthases and only minimal information on the molecular basis for catalysis is known. The Pasteurella multocida hyaluronan synthase (PmHAS) catalyzes the polymerization of the alternating beta1,3-N-acetylglucosamine-beta1,4-glucuronic acid sugar chain by the sequential addition of single monosaccharides to the non-reducing termin...

Aspartate aminotransferase (AAT) catalyzes amino group transfer from glutamate (Glu) or aspartate (Asp) to a keto acid acceptor-oxaloacetate (OA) or alpha-ketoglutarate (KG), respectively. Data presented here show that AAT catalyzes two partial reactions resulting in isotope exchange between 3H-labeled Glu or 3H-labeled Asp and the cognate keto acid in the absence of the keto acid acceptor requ...

Diaminopimelic acid epimerase was purified from Escherichia coli. The enzyme is a monomer of Mr = 34,000. Diaminopimelic acid epimerase is not a pyridoxal phosphate-dependent enzyme: there is no evidence for pyridoxal phosphate in the ultraviolet spectrum of the purified enzyme, and the epimerase is not inactivated by carbonyl reagents such as hydroxylamine and sodium borohydride. Exchange of t...