Other interactions in mononuclear systems

OTHER INTERACTIONS IN MONONUCLEAR SYSTEMS 8.6.1 Spin-admixed states... 

As with normal hydrocarbon-based surfactants, polymeric micelles have a core-shell structure in aqueous systems (Jones and Leroux, 1999). The shell is responsible for micelle stabilization and interactions with plasma proteins and cell membranes. It usually consists of chains of hydrophilic nonbiodegradable, biocompatible polymers such as PEO. The biodistribution of the carrier is mainly dictated by the nature of the hydrophilic shell (Yokoyama, 1998). PEO forms a dense brush around the micelle core preventing interaction between the micelle and proteins, for example, opsonins, which promote rapid circulatory clearance by the mononuclear phagocyte system (MPS) (Papisov, 1995). Other polymers such as pdty(sopropylacrylamide) (PNIPA) (Cammas etal., 1997 Chung etal., 1999) and poly(alkylacrylicacid) (Chen etal., 1995 Kwon and Kataoka, 1995 Kohorietal., 1998) can impart additional temperature or pH-sensitivity to the micelles, and may eventually be used to confer bioadhesive properties (Inoue et al., 1998). 

Systemic and local immune responses, humoral and cellular, are mounted by the host but these are not associated with host protection. Necrosis of Peyer s patches, which may lead to intestinal perforation, is attributed to interaction of bacterial factors and host immune response. It is also interest that in typhoid fever there is no strong association with HIV infection, whereas in HIV infection there is an increased incidence of non-typhi Salmonella infection. Headache, pharyngitis and arthralgia may be present. Gastrointestinal symptoms are usually constipation, abdominal pain and tenderness. Other symptoms which may occur are diarrhea, the pea soup type containing inflammatory mononuclear cells. The biliary tree and liver is involved presenting cholecystitis and hepatitis. Splenomegaly may develop. 

This ideal picture is better approached using the second strategy, where the intercomponent interaction is likely to be much smaller. Here, mononuclear models of the metal polypyridine fragments are readily available, and their properties are likely to be strictly maintained in the polynuclear system. Possible problems, on the other hand, are related to the synthetic sequence needed (first link together two free polypyridine ligands, and then bind stepwise the two metals). Furthermore, the non-rigid nature of the binuclear complex obtained... 

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