Functional assays materials

Another report demonstrates the capability of providing quantitative information on the extent of conversion of a solid-phase material. This method may be applicable to a wide range of reaction chemistries and resin-supported materials. These authors use NMR to quantify the extent of the derivatization of functionalized polymeric material with a fluorinated substrate. Thus the rate of the reaetion of Merrifield resin with 2-lluo-rophenol was examined. At various time intervals portions of the reacting resins were removed and were exhaustively reacted with excess 4-lluo-rophenol. Analysis of the resin samples shows two signals (Scheme 2.9), one for the 2-fluoro derivative at -134 ppm and the other for the 4-fluoro derivative at -124ppm. Quantitative information on the extent of the reaction was obtained by measuring the relative intensities of the resin bound fluorine and a known concentration of an internal standard in solution, such as fluorobenzene. It was noted that there needed to be a sufficient time delay between the RF pulses so that the solid-phase and solution-phase nuclei would be similarly relaxed in the F NMR spectra. This method provided excellent correlation for resin-bound F atom content in samples containing 30 mg resin samples blended to various extents with 100% 2-fluorophenyl Merrifield ether and unfunctionalized Merrifield resin. This fluorophenol based assay was then used to optimize the attaehment of an epoxide to the Merrifield resin (Scheme 2.10). The alkylation reaetion was monitored at... 

The hulls are the first material removed from the process to merit concern in respect to safeguards. These represent a possible route for special nuclear material (SNM) to be clandestinely removed from the system. Special instmmentation is used to assay the hulls containers for residual SNM. This step not only monitors the dissolver for proper functioning, but also serves an accountancy function as a material access area portal and enables the satisfaction of contractual requirements regarding process losses (40). 

The effect of the material on cellular metabolism is also an important measure of biocompatibility. To determine such effects, cultured ex vivo cells can be exposed to the polymer and the growth rates compared to controls [216,217], The metabolic function of the cells can be tested by assay for production of a marker enzyme. An additional advantage of this type of test is that it avoids the use of live animals. 

The principle of the human skin model test is that the test material is apphed topically for up to 4h to a three-dimensional human skin model, comprising at least a reconstructed epidermis with a functional stratum comeum (outermost layer of the skin). The human skin models can come from various sources, but they must meet certain criteria. Corrosive materials are identified by their abdity to produce a decrease in cell viabdity (as determined, e.g., by using a dye reduction assay) below defined threshold levels at specified exposure periods. The principle of the test is in accordance with the hypothesis that corrosive chemicals are able to penetrate the stratum comeum (by diffusion or erosion) and are sufficiently cytotoxic to cause cell death in the underlying cell layers. 

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