Analogy and Limitations

In the 1950s, Kuhn had already observed the peculiar behavior of liquids swelling polymeric gels [5]. Indeed, a strong analogy can be proposed between solvent 

Using TPM as described in Section 10.2 on swollen polymers can give access to the mesh size distribution (MSD) in the swollen state. The ability of the polymer to swell is connected to the reticulation level, which in turn can vary greatly during polymer aging. 

Another limitation in applying TPM to gels comes from the necessary extrapolation of calibration curves to high values of Rp not covered by the calibration itself. The use of macroporous reference samples would indeed be very beneficial to ascertain the calibration curves. In the following sections some examples will illustrate the use of TPM to characterize soft materials. 

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The discovery of brassinolide by scientists at USDA led to the development of a new group of plant growth substances, termed brassinosteroids, which have the potential for increasing crop yields and biomass. The chapter summarizes the USDA s contributions to brassinosteroids, which include isolation and identification of brassinolide, synthesis of brassinolide and its analogs, and limited biological and field studies on brassinosteroids. An overview of the current data requirements for the registration of brassinosteroids as biochemical pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act is presented. 

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