Intriguing Open Questions

KdV equation (equation 3.45), the nature of any deeper mathematical connection, if there is one, remains an intriguing open question,... 

While CT mediated by the DNA base stack may not be completely characterized mechanistically, that it does occur is undeniable. This remarkable chemistry, inherent to DNA, has opened the door to a myriad of possible applications, and provoked intriguing questions regarding biological consequences. 

The presence of ascorbic acid as a co-substrate enhanced the rate of the Ru(EDTA)-catalyzed autoxidation in the order cyclohexane < cyclohexanol < cyclohexene (148). The reactions were always first-order in [H2A]. It was concluded that these reactions occur via a Ru(EDTA)(H2A)(S)(02) adduct, in which ascorbic acid promotes the cleavage of the 02 unit and, as a consequence, O-transfer to the substrate. While the model seems to be consistent with the experimental observations, it leaves open some very intriguing questions. According to earlier results from the same laboratory (24,25), the Ru(EDTA) catalyzed autoxidation of ascorbic acid occurs at a comparable or even a faster rate than the reactions listed in Table III. It follows, that the interference from this side reaction should not be neglected in the detailed kinetic model, in particular because ascorbic acid may be completely consumed before the oxidation of the other substrate takes place. 

The possibility of a finite value for aM is an intriguing idea worth studying. Indeed, it was discussed very early by Gell-Mann and Low in their classic and seminal paper QED at small distances [67], in which they showed that it is something to be seriously considered. However, they could not decide from their analysis whether enj is finite or infinite. The standard QED statement that it is infinite was established later on the basis of perturbative calculations. Nevertheless, and contrary to an extended belief, the alternative presented by Gell-Mann and Low has not been really settled. It is still open, in spite of the many attempts to clarify this question. 

The role of quantum coherence in promoting the efficiency of the initial stages of photosynthesis is an open and intriguing question. 

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