This study examined the effects of the sodium salts of aliphatic dicarboxylic acids (DCAs) on the dynamic mechanical properties and morphology of two sets of poly(styrene-co-sodium methacrylate) (MNa) and poly(styrene-co-sodium styrenesulfonate) (SNa) ionomers. When the DCA content was relatively low, the ionic moduli of the MNa and SNa ionomers increased but the matrix and cluster glass transition temperature (T g ) did not change significantly. The increasing ionic modulus was almost independent of the type of the ionic groups of the ionomer, and the chain length of DCAs. When a large amount of the sodium succinate (DCA4) was added to the MNa and SNa ionomers, the ionic moduli of the two ionomers increased strongly but the matrix and cluster T g 's increased slightly and significantly, respectively. In the case of sodium hexadecanedioate (DCA16), DCA16 increased the ionic moduli of the two ionomers. The addition of DCA16 changed the matrix and cluster T g 's of the MNa ionomer slightly, but decreased the cluster T g of the SNa ionomer significantly with no change in the matrix T g . In addition, the DCA-containing ionomers showed an X-ray diffraction peak indicating the presence of ordered domains of DCAs in the ionomers. Hence, DCA4 acts mainly as a reinforcing filler in MNa and SNa systems. In the case of DCA16, it initially behaved like a filler but also functioned as a preferential plasticizer for the clusters at high content.
A series of pluronic F127 conjugated PAMAM dendrimer generation 5 were prepared to evaluate the potential use of dendrimer-pluronic conjugates as a delivery agent of antisense oligonucleotides. The structural features of the conjugates were identified by FT-IR and 1H-NMR spectra. The prepared dendrimer generation 5-pluronic F127 conjugates showed particle size in the range of 50 to 130 nm with reduced zeta potential. The electrophoretic property of conjugates was further confirmed by capillary zone electrophoresis (CZE), demonstrating the decrease in electrophoretic mobility of conjugates as the number of pluronic F127 on surface of dendrimer increases. The number of free amino groups on a pluronic F127 conjugated dendrimer was quantitatively determined by fluorescamine assay, measuring the fluorescence intensity of amino groups reactive to fluorescamine on dendrimer generation 5-pluronic F127 conjugates. In MTT assay, dendrimer G5-pluronic F127 conjugates were safe on gingival fibroblast cells and acute toxicity was reduced as the mole ratio of dendrimer to pluronic increased. Complex formation of dendrimer G5-pluronic F127 conjugates with oligonucleotides was dose dependent.
A divergent synthetic route to (+)-castanospermine 1 and (+)-6-epicastanospermine 2 has been developed via phenylselenoamidation of trichloroacetimidate derived from allylic alcohol 7, and dihydroxylations of trans-olefins 14 and 18 to dispose the three contiguous asymmetric centers, one amino group and two hydroxy groups.
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