The substitution of aluminum with scandium in the mixed yttrium aluminum scandium garnets, Y 3 Sc x Al 5--x O 12 (x ¼ 0, 0.05, 0.5, 1.5), was studied for the first time using 27 Al magic angle spinning (MAS), multiple quantum (MQ) MAS NMR, and 45 Sc MAS NMR. The aluminum and scandium quadrupole coupling constants and isotropic chemical shifts were evaluated for all garnets under study. 27 Al 2D spectra evidenced variation of the isotropic shifts over the aluminum sites in the mixed garnets.

Solid polymer electrolytes based on polyurethane/poly(dimethylsiloxane) segmented copolymers (PS55) have been characterized by differential scanning calorimetry (DSC), ionic conductivity, and multinuclear solid-state NMR measurements. The results of DSC measurements indicate the formation of transient cross-links between Li+ ions and the ether oxygens on complexation with LiClO4, resulting in an increase in the soft segment T g. However, the soft segment T g remains almost invariant at high salt concentration. There is a conductivity jump at around 310−330 K that the behavior of ionic conductivity changes from Arrehnius- to Vogel−Tamman−Fulcher (VTF)-type behavior. Below this jump temperature, the conductivity follows Arrehnius-like behavior, implying a diffusing mechanism for transport of the charge carriers where the charge carriers are decoupled from the segmental motion of the polymer chain. By contrast, the diffusion of charge carrier is assisted by the segmental motions of the polymer chains above the jump temperature, suggested by the VTF-like behavior. At high salt concentration, the ionic conductivity decreases due to the formation of ion pairs and/or ion clusters. Solid-state 13C NMR results from cross-polarization time constant (T CH) measurements along with two-dimensional (2D) WISE NMR suggest that a significant decrease in the mobility of the soft segment as the salt is added. Polysiloxane backbone is not affected until at a higher salt concentration, as observed by the line width change in the 29Si NMR spectrum. The onset temperature of 7Li motional line narrowing is correlated with the soft segment T g. The activation energies obtained from ionic conductivity, 7Li line width, and T 1 measurements indicate that there is a strong correlation between the ionic conductivity of the solid polymer electrolyte and the mobile lithium cation.

Three new phloroglucinols, garcinielliptones K (1), L (2), and M (3), and two new terpenoids, garcinielliptones N (4) and O (5), have been isolated from the seeds of Garcinia subelliptica. The structures of 1-5 including their relative configurations were elucidated by spectroscopic methods and supported by computer-generated molecular modeling. Compounds 2 and 3 showed potent inhibitory effects on the release of beta-glucuronidase, and on beta-glucuronidase and histamine, respectively, from peritoneal mast cells stimulated with p-methoxy-N-methylphenethylamine (compound 48/80) in a concentration-dependent manner. Compounds 2 and 3 showed potent effects on NO production in culture media of RAW 264.7 cells in response to lipopolysaccharide (LPS). Compound 2 also showed a potent effect on NO production in culture media of N9 cells in response to LPS/interferon-gamma (IFN-gamma).

Two new protopine-type alkaloids, argemexicaine A (1) and argemexicaine B (2), along with thirteen known alkaloids, were isolated from MeOH extracts of Formosan Argemone mexicana L. (Papaveraceae). Physical and spectral analyses, particularly IR and thermo-modulated 1D and 2D NMR, were used to determine the transannular conformations of the isolated protopine-type alkaloids. The known benzo[ c]phenanthridine (+/-)-6-acetonyldihydrochelerythrine (5) exhibited significant anti-HIV activity in H9 lymphocytes with EC50 and TI (Therapeutic Index) values of 1.77 microg/mL and 14.6, respectively.