Self-generation, protective coating

The actinide metals are electropositive and reactive, apparently becoming increasingly so with atomic number. They tarnish rapidly in air, forming an oxide coating which is protective in the case of Th but less so for the other elements. Because of the self-heating associated with its radioactivity (100 g Pu generates 0.2 watts of heat) Pu is best stored in circulating dried air. All are pyrophoric when finely divided. 

Kim and coworkers adapted the periphery of PPIs for a similar, albeit more ionic, coordination with cylindrical cucurbituril (CB 38) units to give a stable, poly(pseudorotaxane) architecture. The required l w(am-monium)-coated scaffolding was accessed via treatment of the dendriiner amine surface with the perfluorophenyl-activated ester of a Ijw(protected) diamine-modified acetate 3 9 followed by deprotection (HBr) of the diamine chains. Dissolution of the polyprotonated framework in H2O followed by the addition of CB afforded the self-assembled product 40. Preliminary studies aimed at decomplexation via treatment with base yielded partial separation. T] (spin-lattice) relaxation experiments with the CB-dendrimer complex showed a sharp increase with higher generations, suggesting that the outer shell possessed attributes of a solid phase such behavior has also been noted by Jansen et al. ... 

Viruses act as self-reproducing intracellular parasites. Although they have no metabolic machinery of their own and are unable to generate ATP or synthesize proteins, they are able to penetrate living cells and put the cell s metabolic machinery to their own use, causing it to manufacture new virus particles instead of normal cell products. Viruses contain either DNA or RNA but not usually both. The nucleic acid that carries the information that instructs the host cell to produce new virus particles is enclosed by a protein coat which protects it from mechanical breakage and enzymic attack. The coat also determines the specificity of the virus, i.e. the nature of the cell that the virus can infect. Bacteria may be infected by viruses known as bacteriophages. 

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