Phototoxic phytoalexins. Processes that compete with the photosensitized production of singlet oxygen by 9-phenylphenalenones

Experiments were performed to elucidate the excited-state behavior of 9-phenylphenalenones, which are phototoxic plant secondary metabolites involved in mechanisms of light-mediated plant defense. Using a combination of time-resolved and steady-state UV/visible spectroscopies, time-resolved IR absorption spectroscopy, time-resolved singlet oxygen phosphorescence measurements and cyclic voltammetry, we provide evidence of an intramolecular charge-transfer process in the excited singlet and the triplet states of 9-phenylphenalenones that modulates the photosensitized production of singlet oxygen.     

Determination of the probability of ultimate ruin by maximum entropy applied to fractional moments

In this work we present two different numerical methods to determine the probability of ultimate ruin as a function of the initial surplus. Both methods use moments obtained from the Pollaczek–Kinchine identity for the Laplace transform of the probability of ultimate ruin. One method uses fractional moments combined with the maximum entropy method and the other is a probabilistic approach that uses integer moments directly to approximate the density.