Perfluorinated compounds in food: a global perspective

Perfluorinated compounds (PFCs) are resistant to breakdown and are turning up in unexpected places around the world, becoming emerging food contaminants. Although these chemicals have been used in countless products since the 1950s, they have been subject to little control until now. There is still an insufficient knowledge of their sources, occurrence, and hazards for food safety decision making. This article provides a comprehensive review of the food contamination levels and dietary intake risks posed by PFCs, as well as the specific methods developed for their determination. It is based on the evaluation of the published literature between 2004 and the beginning of 2010, with special emphasis on those reports of the last two years and in the examination of the growing body of studies on the exposure assessment and food occurrence of PFCs. The current state-of-the art and future perspectives in extraction, clean-up, detection, identification, confirmation, and quantification highlighting the advantages and limitations of each technique have been summarized. How much is known about the sources and pathways of food web and human exposure, which is needed to control and manage the release of these emerging toxic contaminants, has also been explained.     

A Formalization of Credit and Responsibility Within the GNDC Schema

We formally define a notion of credit and responsibility within the Generalized Non Deducibility on Compositions framework. We investigate the validity of our definitions through some examples discussed in the literature.     

Fractionation of reactive perfluoropolyoxyalkylene oligomers

Fractional distillation, solubility fractionation, and column chromatographic separation have been applied in the study of fractionation of perfluoropoly(oxymethylene-co-oxy-ethylene) oligomers with ? CH₂OH end units, containing mono and bifunctional species. With a suitable choice of conditions, all three techniques proved to be useful for the preparation of fractions with narrow molecular weight distribution. Column chromatography allowed the separation of fractions having, in addition, sharp mono and bifunctionality. On the bsis of the experimental results, general indications for designing reactive oligomers fractionation procedures are discussed, prevalently centered on the copolymer end effect, which is typically present in this kind of compound. © 1995 John Wiley & Sons. Inc.     

Antiproliferative agents that interfere with the cell cycle at the G1-->S transition: further development and characterization of a small library of stilbene-derived compounds

In this continuation of our research on derivatives containing the stilbene privileged structure or that are derived from it, we report the results of further studies carried out on the previously initiated collection of compounds. We used a parallel synthetic approach to rapidly obtain small sets of compounds and started the annotation of the library in progress by calculating some physicochemical properties to be eventually correlated with biological activities. A pharmacophore for the antiproliferative activity was also built to summarize the features of the library. We evaluated the antiproliferative and pro-apoptotic activities of all compounds as well as the cell-cycle effects of some representative compounds. After in-depth investigations, 3'-phenyl-[1,1';4',1']terphenyl-4,3',5'-triol showed the most interesting biological profile, as it interferes with cell-cycle progression at the G(1)-->S transition, acting on retinoblastoma phosphorylation and inducing cell differentiation.     

Galloflavin (CAS 568-80-9): a novel inhibitor of lactate dehydrogenase

One of the most prominent alterations in cancer cells is their strict dependence on the glycolytic pathway for ATP generation. This observation led to the evaluation of glycolysis inhibitors as potential anticancer agents. The inhibition of lactate dehydrogenase (LDH) is a promising way to inhibit tumor cell glucose metabolism without affecting the energetic balance of normal tissues. However, the success of this approach depends chiefly on the availability of inhibitors that display good selectivity. We identified a compound (galloflavin, CAS 568‐80‐9) which, in contrast to other inhibitors of human LDH, hinders both the A and B isoforms of the enzyme. To determine the mechanism of action, we collected LDH‐A and ‐B inhibition data in competition reactions with pyruvate or NADH and evaluated the results using software for enzyme kinetics analysis. We found that galloflavin inhibits both human LDH isoforms by preferentially binding the free enzyme, without competing with the substrate or cofactor. The calculated K_i values for pyruvate were 5.46 μM (LDH‐A) and 15.06 μM (LDH‐B). In cultured tumor cells, galloflavin blocked aerobic glycolysis at micromolar concentrations, did not interfere with cell respiration, and induced cell death by triggering apoptosis. To our knowledge, the inhibition of LDH is, to date, the only biochemical effect described for galloflavin. Because galloflavin is not commercially available, we also describe herein a procedure for its synthesis and report its first full chemical characterization.     

Lignin nanoparticles by ultrasonication and their incorporation in waterborne polymer nanocomposites

Lignin nanoparticles (nanolignin, NL) were prepared in this work by ultrasonic treatment of softwood kraft lignin to obtain lignin‐water dispersions with excellent colloidal stability. A thorough characterization of the chemical, physical, and morphological properties of the new NL particles allowed for direct comparisons with the untreated parent material. Such NL particles were incorporated into a waterborne thermoplastic polyurethane matrix at different concentrations to yield bio‐based nanocomposite materials. The effect of the bio‐filler type (NL vs. untreated lignin) and loading on the chemical, physical, thermal, and morphological characteristics of the resulting nanocomposites was extensively investigated. In addition, tensile tests carried out on these systems highlighted the superior mechanical properties of NL‐based nanocomposites compared to composite materials incorporating untreated lignin. The results of this study provide a direct demonstration of an easy and environmentally friendly approach to obtain waterborne polyurethane‐based nanocomposites reinforced with NL in a relatively straightforward and accessible way and clearly evidence the potential of lignin nanoparticles as fully bioderived fillers for advanced nanocomposite applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45318.     

Differences Between People Who Use Only Facebook and Those Who Use Facebook Plus Twitter

Facebook (FB) and Twitter are popular social networking sites. This study examined differences between those who use both sites versus only FB, to test the hypothesis that mono-users differ in their personality characteristics from users active in both websites. Participants were 205 undergraduate students: 96 only used FB, 109 used FB and Twitter. Participants who used both sites reported significantly lower loneliness, higher number of FB friends, and lower number of minutes spent online, as compared to those who used only FB. Loneliness was positively associated with FB use only in those who used FB alone but was negatively associated with and negatively predicted both FB and Twitter use in those who used both websites. Findings suggest that more intense use of online interactions is more frequently found in mono-users (people using only Facebook) as compared to those using both websites, and it is predicted by increased feelings of loneliness. The current study findings provide additional insights on what personality factors may make some people prone to excessive use of social networking sites.