Overlapping water relations

Part 5 Overlapping Water Relations and Material Sciences for the Improvement of Quality Products... 

Some of the subjects discussed in Sessions VI (chaired by Dr. Pilar Buera) and VII (chaired by Dr. Peter Lillford) were included in Chapters 17 to 20 of this book, under a general title "Overlapping Water Relations and Material Sciences for the Improvement of Quality Products Past, Present, and Future." Researchers from pharmaceutical and food sciences were gathered to provide a clear picture of recent advances in understanding the preservation of biomolecule functionality in restricted water environments and how to manage the adverse effects of water on sensitive components. In the last session. Dr. Theodore Labuza dedicated a space to the subject "Material Science in Food Technology and Pharmaceutics" inspired by Dr. Marcus Karel. Those who were his former students (Theodore Labuza,... 

P2j Z = 2 D = 1.57 R = 0.048 for 931 intensities. The base exists in the thioxo form, with C-8=S and N-7 protonated. The 8-thio substituent causes the base to assume the syn (—102.6°) orientation. The o-ribosyl group is 2T3 (174.8 °, 44.1 °). The exocyclic, C-4 -C-5 bond orientation is trans (—173.2°). This does not favor intramolecular hydrogen-bonding of 0-5 to N-3 of the syn base. The C=S distance is 166.8 pm. The S atom is involved in a weak, acceptor hydrogen-bond to a water molecule, S H-O(w) = 361 pm. The bases are stacked head-to-tail, with overlap of the C=S bonds and the purine ring, in contrast to the known, related structure l-/ -D-ribofuranosyl-2-thioxo-3ff-benzimidazole,197 where similar head-to-tail stacking of the bases involves overlap of the base rings only. 

Another limitation of the Poisson-Boltzmann approach is that the interaction between two surfaces immersed in water might not be exclusively due to the electrolyte ions. For instance, water has a different structure in the vicinity of the surface than in the bulk and the overlapping of such structures generates a repulsion even in the absence of electrolyte [20]. In this traditional picture, the hydration repulsion is not related to ion hydration actually it is not related at all to electrolyte ions. However, as recently suggested [21], this hydration interaction can still be accounted for within the Poisson-Boltzmann framework, assuming that the polarization is not proportional to the macroscopic electric field, but depends also on the field generated by the neighboring water dipoles and by the surface dipoles. 

---