Type II topoisomerases are ubiquitous enzymes that control the topology and higher order structures of DNA. Type IIA enzymes have the remarkable property to sense locally the global DNA topology. Although many theoretical models have been proposed, the molecular mechanism of chiral discrimination is still unclear. While experimental studies have established that topoisomerases IIA discriminate ...

chiral pyrrolidines and pyrrolizidines with spirooxindole ring systems are the central skeletons for numerous alkaloids and pharmacologically important compounds. gelesmine, pseudotabersonine, formosanine, isoformosanine, morroniside and mitraphylline are some of the alkaloids containing spirooxindole ring systems. derivatives of spirooxindole find very wide biological applications as anti micr...

the distribution behavior of ofloxacin enantiomers was examined in the aqueous and organic solvent of a two-phase system containing chiral selector l-tartarate. the effect of extraction equilibrium time, buffer ph, organic solvents and length of alkyl chain of l-tartarate on the partition coefficients and enantioselectivity of racemic ofloxacin were investigated, respectively. the l-tartarate f...

Ab initio calculations at HF/6-31G* level of theory for geometry optimization and MP2/6-31G*//HF/6-31G* for a single point total energy calculation are reported for the importantenergy-minimum conformations and transition-state geometries of 1, 3-diazacyclohepta-1, 2-diene (2) and 1, 3-diazacycloocta-1, 2-diene (3). The C2 symmetric twist-chair (2-TC)conformation of 2 is calculated to be 7.4 kJ...

Enantiopure chiral amidic derivatives of sinapic acid were oxidised with hydrogen peroxide using horseradish peroxidase (HRP) as the catalyst to give the aryltetraline dilignol thomasidioic acid. Trans-diastereoselectivity and enantioselectivity in the formation of thomasidioic acid was observed. Computational methods show that the enantioselectivity is controlled by the beta-beta oxidative cou...

We investigate the stability of the hidden sector gaugino condensate in a SL(2,Z)-invariant supergravity model inspired by the E8⊗E8 heterotic string, using the chiral superfield formalism. We calculate the Plancksuppressed corrections to the “truncated approximation” for the condensate value and the scalar potential. A transition to a phase with zero condensate occurs near special points in mo...

– We consider the stability of the superconducting phase for spin-triplet p-wave pairing in a quasi-two-dimensional system. We show that in the absence of spin-orbit coupling there is a chiral contribution to spin fluctuation feedback which is related to spin quantum Hall effect in a chiral superconducting phase. We show that this mechanism supports the stability of a chiral p-wave state. Coope...

Cosmic strings in realistic particle physics models have fermion zero modes in the string core. Such zero modes change the underlying cosmology; for example, the string can carry a current. We consider the stability of fermion zero modes to interactions with particles in the surrounding plasma. We also consider cosmological constraints on such theories, particulary those with a chiral fermion z...

The stabilization of the metastable 180 degrees twist state in a bistable chiral splay nematic liquid crystal device is studied. The stability of the metastable 180 degrees twist state is explained using the azimuthal anchoring strength, which is a function of the twist elastic constant and the cell gap. A stable 180 degrees twist state as well as the permanent retention time can be obtained by...

The formation and high stability of the H-bond-driven supramolecular architectures of the syn and anti isomers of the dioxime of bicyclo[3.3.1]nonane-3,7-dione were investigated by single crystal X-ray diffraction, NMR, FTIR, and molecular modeling. Self-assembly of the achiral syn isomer into a cyclic trimer (supramolecular wheel) and of the chiral anti isomer into homochiral cyclic dimers was...