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In 2019, the United States consumed over 57 million metric tons (MMT) of plastic with less than 7% recovered for reuse. This study provides an updated material flow analysis at national and regional scales for all durable and single-use plastics in the United States. From this material flow analysis, we develop a series of alternative future national plastic flow scenarios that envision a scale-up of recycling technologies, incorporating technical limitations and sorting infrastructure constraints. The results suggest that a maximum of 68% (24 MMT) of plastic waste could be diverted from landfills by scaling up existing commercial recycling technologies. Based on the current technological landscape, reaching near-zero waste is only possible if processes that are operating at pilot and laboratory scales can be effectively scaled and coupled with improved sorting infrastructure. Through these scenarios with increased recycling, the availability of postconsumer resin stocks could increase by 22–43 MMT.

Abstract:Ancient biographies of poets are usually thought to take much of their information from the subjects' poems. The relationship between poetry and biography is in fact more complex, and I take as a case study the information about Solon in Ath. Pol. 5–12. Aristotle does use Solon's poetry as a means of establishing the past, but it is more often the case that he reads other traditions into the poetry than that he extrapolates new traditions from the poetry alone. Aristotle also uses his historical knowledge to interpret and comment on the poems in a kind of exegesis.

Epigenetic modification of DNA leads to changes in gene expression. DNA methyltransferases (DNMTs) comprise a family of nuclear enzymes that catalyze the methylation of CpG dinucleotides, resulting in an epigenetic methylome distinguished between normal cells and those in disease states such as cancer. Disrupting gene expression patterns through promoter methylation has been implicated in many malignancies and supports DNMTs as attractive therapeutic targets. This review focuses on the rationale of targeting DNMTs in cancer, the historical approach to DNMT inhibition, and current marketed hypomethylating therapeutics azacytidine and decitabine. In addition, we address novel DNMT inhibitory agents emerging in development, including CP-4200 and SGI-110, analogs of azacytidine and decitabine, respectively; the oligonucleotides MG98 and miR29a; and a number of reversible inhibitors, some of which appear to be selective against particular DNMT isoforms. Finally, we discuss future opportunities and challenges for next-generation therapeutics.

To determine the feasibility of implementing a smallpox vaccination program aboard an aircraft carrier in conjunction with anthrax vaccination.

We report the predicted sequence of four vegetative homologues (Blec1,2,3 and 4) of the pea seed lectin. This study indicates that, in contrast to the single-copy pea seed lectin (Kaminski et al., Plant Mol Biol 9: 497–507, 1987), the pea vegetative lectin is transcribed by at least four members of a highly conserved multigene family whose members are only distantly related to the pea seed lectin at the primary amino-acid sequence level. For example, Blec1 shares only 38% amino-acid identity with the pea seed lectin. However, molecular homology modelling predicts that Blec1 probably forms a similar tertiary structure to the pea seed lectin.

The flexibility of surface loops plays an important role in protein–protein and protein–peptide recognition; it is commonly studied by Molecular Dynamics or Monte Carlo simulations. We propose to measure the relative backbone flexibility of loops by the difference in their backbone conformational entropies, which are calculated here with the local states (LS) method of Meirovitch. Thus, one can compare the entropies of loops of the same protein or, under certain simulation conditions, of different proteins. These loops should be equal in size but can differ in their sequence of amino acids residues. This methodology is applied successfully to three segments of 10 residues of a Ras protein simulated by the stochastic boundary molecular dynamics procedure. For the first time estimates of backbone entropy differences are obtained, and their correlation with B factors is pointed out; for example, the segments which consist of residues 60–65 and 112–117 have average B factors of 67 and 18 Ų, respectively, and entropy difference T ΔS = 5.4 ± 0.1 kcal/mol at T = 300 K. In a large number of recent publications the entropy due to the fast motions (on the ps-ns time scale) of N–H and C–H vectors has been obtained from their order parameter, measured in nuclear magnetic resonance spin relaxation experiments. This enables one to estimate differences in the entropy of protein segments due to folding–unfolding transitions, for example. However, the vectors are assumed to be independent, and the effect of the neglected correlations is unknown; our method is expected to become an important tool for assessing this approximation. The present calculations, obtained with the LS method, suggest that the errors involved in experimental entropy differences might not be large; however, this should be verified in each case. Potential applications of entropy calculations to rational drug design are discussed. Proteins 29:127–140, 1997. © 1997 Wiley-Liss, Inc.

The acoustical behavior of a harpsichord modeled after 17th‐century Flemish prototypes was studied using both experimental and analytical techniques. The vibrational modes of its enclosed air volume were measured and found to correspond closely to those predicted by the J0 and J9 solutions to the Bessel equation for a wedge shaped space. A modal analysis of the complete harpsichord revealed that the soundboard has 36 vibrational modes over a frequency range of 0 to 600 Hz, and that there are numerous modes where the instrument’s case has a significant amplitude of motion. Additional information is reported showing that the acoustic output of the harpsichord is reasonably flat over a frequency range of 50–2000 Hz. It is concluded that the resonance behavior of both the soundboard and the enclosed air are important to the tone quality of the harpsichord, and that its generally uniform acoustic output results from the excitation of a large number of wood and air modes by the string partials.

The flexibility of surface loops plays an important role in protein–protein and protein–peptide recognition; it is commonly studied by Molecular Dynamics or Monte Carlo simulations. We propose to measure the relative backboneflexibility of loops by the difference in their backbone conformational entropies, which are calculated here with the local states (LS) method of Meirovitch. Thus, one can compare the entropies of loops of the same protein or, under certain simulation conditions, of different proteins. These loops should be equal in size but can differ in their sequence of amino acids residues. This methodology is applied successfully to three segments of 10 residues of a Ras protein simulated by the stochastic boundary molecular dynamics procedure. For the first time estimates of backbone entropy differences are obtained, and their correlation with B factors is pointed out; for example, the segments which consist of residues 60–65 and 112–117 have average B factors of 67 and 18 Å2, respectively, and entropy difference TΔS= 5.4 ± 0.1 kcal/mol at T= 300 K. In a large number of recent publications the entropy due to the fast motions (on the ps‐ns time scale) of N–H and C–H vectors has been obtained from their order parameter, measured in nuclear magnetic resonance spin relaxation experiments. This enables one to estimate differences in the entropy of protein segments due to folding–unfolding transitions, for example. However, the vectors are assumed to be independent, and the effect of the neglected correlations is unknown; our method is expected to become an important tool for assessing this approximation. The present calculations, obtained with the LS method, suggest that the errors involved in experimental entropy differences might not be large; however, this should be verified in each case. Potential applications of entropy calculations to rational drug design are discussed. Proteins 29:127–140, 1997. © 1997 Wiley‐Liss, Inc.