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The molecular mechanism of platinum-based drugs in concomitant chemoradiation therapy relies on enhancement of DNA damage in cancer cells, particularly that of detrimental clustered lesions and cross-links induced by the abundant low-energy electrons (LEEs) generated by ionizing radiation. We provide the complete 1−20 eV electron-energy dependence of the yields of all conformational LEE-induced lesions to biological DNA, when it binds to five molecules of the chemotherapeutic drug cisplatin. Recording at 1 eV intervals clearly show that the enhancement of all lesions is particularly intense at the energies of coreexcited transient molecular anions (i.e., TMAs at 5, 6, and 10 eV). New TMAs are observed at 14 and 18 eV, only in yield functions of cisplatin-DNA complexes. Enhancements of all lesions by cisplatin are quantified over the 1−20 eV range, where maxima appear at 14 and 18 eV. The most detrimental lesions to cell survival exhibit the highest enhancements by factors of 2−3. Whereas no cluster lesions are induced by electrons of energy <5 eV in DNA, LEEs of any energy cause clustered damages in the complex. These results confirm the current notion that LEEs and TMAs play a dominant role in the molecular mechanism of platinum-drug chemoradiation therapy.

Water activities of the CsCl–MgCl2–H2O ternary system and its sub-binary systems were elaborately measured by an isopiestic method at 298.15 K. The solubility of this ternary system at 298.15 K was also measured by two different methods, namely isothermal method and Flow-Cloud-Point method. The solubilities measured by the two different methods were consistent with each other. A Pitzer model was used to represent the thermodynamic properties and calculate the solubility isotherms for the CsCl–MgCl2–H2O ternary system at 298.15 K. Both the equal water activity lines and the solubility isotherms are calculated with parameters reported in literature. It was found that only the calculated equal water activity lines with the parameters reported by Scharge et al. are consistent with the experimental values of this work. However, all the calculated solubility isotherms deviated from the experimental data in this work. New set of ternary parameters were obtained by fitting the water activities and solubility data of this work. Using the new parameters, the calculated equal water activity lines and solubility isotherms agreed with experimental values measured in this work.

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