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Peptide nucleic acid (PNA) containing arginine side chains exhibited remarkable uptake properties while maintaining Watson-Crick recognition with complementary DNA strands is demonstrated. Evidence is provided that PNA could be selectively modified to facilitate uptake into mammalian cells.

The ε-β fishlike phase diagram of the system [C16mim]Br/[Omim]Tf2N/water was constructed in the presence of different additives (alcohol and inorganic salt). From the diagram some additive-dependent characteristic physicochemical parameters were obtained. Results show that with the increase of the alkyl chain length of alcohols, the solubility of the alcohol in [Omim]Tf2N, and the optimum solubilization parameter (SP*) decrease, while the maximum alcohol width (△ε) for the phase inversion and the mass fraction of the alcohol in the balanced interfacial film (Ain) increase. For inorganic salts, an increase in [NaCl], or an increase of the radius of halides (X-) at constant [NaX], or the substitution of the divalent anion SO42- by the same molar concentration of monovalent anion Cl- makes both SP* and △ε increase, but Ain decrease. Overall, the alcohol effect on the phase behavior of the microemulsion is greater than the salt effect, and the composition effect of an inorganic salt is greater than the concentration effect. These effects could be rationalized based on their influence on the dissolution and aggregation behavior of the surfactant [C16mim]Br in the system. [ABSTRACT FROM AUTHOR]

Serum samples collected from California women at different time periods: 1960s (n = 40), 1980s (n = 30), and 2009 (n = 35) were examined for the presence of 12 perfluorinated compounds (PFCs) using an online SPE-HPLC-MS/MS method. At each time period, perfluorooctane sulfonate (PFOS) was present at the highest concentration, followed by perfluorooctanoic acid (PFOA, except in the 1960s). We found the highest levels of PFOS (median = 42.1 ng/mL) and perfluorohexane sulfonate (PFHxS, median = 1.56 ng/mL) in the 1960s samples, possibly reflecting widespread use of precursor PFCs. PFOS showed a statistically significant drop from the 1960s to the 1980s (28.8 ng/mL ) and to 2009 (9.0 ng/mL ), the latter being in agreement with national data. For PFOA, there was an approximately 10-fold increase in median concentrations from the 1960s (0.27 ng/mL) to the 1980s (2.71 ng/mL), and a slight drop in the 2009 samples (2.08 ng/mL). For longer chain perfluorocarboxylic acids (PFCAs), there was a continuous build-up in serum from the 1960s to 2009. To our knowledge, this is the first study to investigate temporal changes of PFCs over the past 50 years. [ABSTRACT FROM AUTHOR]