Effect of Pregnancy on Left Ventricular Motion (Twist) in Women With Aortic Stenosis

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• 作者：Nikolaos Tzemos ; C ; ice K. Silversides ; Shemy Carasso ; Harry Rakowski ; Samuel C. Siu
• 关键词：DNA ; Charge transfer ; Excimer ; Charge migration ; CASPT2
• 刊名：The American Journal of Cardiology
• 出版年：2008
• 出版时间：15 March 2008
• 年：2008
• 卷：101
• 期：6
• 页码：870-873
• 全文大小：96 K

文摘

Charge transport in DNA strands has been studied by characterizing on theoretical grounds the lowest doublet states of the oxidized cytosine homodimer (CC⁺) and adenine–cytosine heterodimer (CA⁺) along the intermolecular separation of the monomers. The high-level quantum-chemical ab initio CASPT2 method and accurate one-electron basis sets have been employed. Both cationic species are found to be bound with comparable binding energies as those of neutral CC and reduced CC⁻. The results suggest that charge transport in DNA and the distinct photophysical attributes related to the polymer can be described within the framework of a unified theory. A cooperative micro-hopping mechanism involving consecutively two-by-two adjacent π-stacked nucleobases is proposed for hole transport along single strands of only dCMP or alternate dAMP and dCMP oligonucleotides. This model could be extrapolated to other combinations of deoxynucleotides and even to double stranded DNA and is expected to be similar for the transport of an excess electron. It is suggested that the efficiency of the process is controlled by the presence and relative location of conical intersections connecting the relevant hypersurfaces.