Breath Figure in Reactive Vapor: A New Route to Nanopore Array

A breath figure (BF)-inspired method for preparing ordered porous films has attracted more and more attention because of its simplicity, low cost, and easy implementation. However, it remains a challenge to use this method to fabricate nanoscale porous structures without designed polymer architecture and auxiliary. Herein, we first report a facile method to fabricate BF arrays with nanopores (nanoBFAs) in reactive vapor. Depending on the chemical reaction between the formic acid (FA) droplet template and the polyvinylpyridine (PVP) segments in copolymer, we successfully create nanoBFAs by casting a PVP-containing copolymer solution in CS₂ in FA vapor. The condensed FA droplets can be instantly fixed by the PVP composition, and thus the growth and the aggregation of adjacent droplets are effectively restricted. Eventually, nanoBFAs are achieved in wide range solution concentration. In addition, binary porous structures with both nano- and microscale topology can be formed by using a FA/water mixed vapor with a one-step BF process. The produced nanoBFA films exhibit excellent antireflection performance with 0.5% reflectance, which is well-preserved even after hydrophobic treatment. This modified BF technique not only facilitates the elucidation of BFA formation mechanism but also opens a new way of fabricating nanoporous structures, which may have potential applications in electronic and optical devices

Drosophila Longevity Assurance Conferred by Reduced Insulin Receptor Substrate <i>Chico</i> Partially Requires <i>d4eBP</i>

<div><p>Mutations of the insulin/IGF signaling (IIS) pathway extend Drosophila lifespan. Based on genetic epistasis analyses, this longevity assurance is attributed to downstream effects of the FOXO transcription factor. However, as reported FOXO accounts for only a portion of the observed longevity benefit, suggesting there are additional outputs of IIS to mediate aging. One candidate is target of rapamycin complex 1 (TORC1). Reduced TORC1 activity is reported to slow aging, whereas reduced IIS is reported to repress TORC1 activity. The eukaryotic translation initiation factor 4E binding protein (4E-BP) is repressed by TORC1, and activated 4E-BP is reported to increase Drosophila lifespan. Here we use genetic epistasis analyses to test whether longevity assurance mutants of <i>chico</i>, the Drosophila insulin receptor substrate homolog, require Drosophila <i>d4eBP</i> to slow aging. In <i>chico</i> heterozygotes, which are robustly long-lived, <i>d4eBP</i> is required but not sufficient to slow aging. Remarkably, <i>d4eBP</i> is not required or sufficient for <i>chico</i> homozygotes to extend longevity. Likewise, <i>chico</i> heterozygote females partially require <i>d4eBP</i> to preserve age-dependent locomotion, and both <i>chico</i> genotypes require <i>d4eBP</i> to improve stress-resistance. Reproduction and most measures of growth affected by either <i>chico</i> genotype are always independent of <i>d4eBP</i>. In females, <i>chico</i> heterozygotes paradoxically produce more rather than less phosphorylated 4E-BP (p4E-BP). Altered IRS function within the IIS pathway of Drosophila appears to have partial, conditional capacity to regulate aging through an unconventional interaction with 4E-BP.</p></div

Robust Microsieves with Excellent Solvent Resistance: Cross-Linkage of Perforated Polymer Films with Honeycomb Structure

Polymeric microsieves with uniform and tunable pores were fabricated with the breath-figure method and sequent vulcanization procedure using commercially available block copolymer polystyrene-<i>b</i>-polyisoprene-<i>b</i>-polystyrene. Uniform pore size and small film thickness endow the microsieves with high size selectivity and low operation pressure, while the cross-linked chemical structure gives them good mechanical properties and excellent chemical and thermal stability. These microsieves are able to separate particles in various media, including corrosive solvents, hot water, and organic solvents. The process reported in this communication is a simple and inexpensive method for the preparation of high-performance microsieves

Robust Microsieves with Excellent Solvent Resistance: Cross-Linkage of Perforated Polymer Films with Honeycomb Structure

Polymeric microsieves with uniform and tunable pores were fabricated with the breath-figure method and sequent vulcanization procedure using commercially available block copolymer polystyrene-<i>b</i>-polyisoprene-<i>b</i>-polystyrene. Uniform pore size and small film thickness endow the microsieves with high size selectivity and low operation pressure, while the cross-linked chemical structure gives them good mechanical properties and excellent chemical and thermal stability. These microsieves are able to separate particles in various media, including corrosive solvents, hot water, and organic solvents. The process reported in this communication is a simple and inexpensive method for the preparation of high-performance microsieves

Survivorship and mortality of male and female adult Drosophila with single and combined mutations of <i>chico</i> and <i>d4eBP</i>.

<p>Cohorts of all genotypes were aged concurrently in two independent trials. Deaths in Trial 2 were recorded beginning at 10 days of age. Mortality rate is plotted as ln(<i>μ</i>_<i>x</i>), estimated as ln(-ln(1-<i>q</i>_<i>x</i>)) where <i>q</i>_<i>x</i> is age-specific mortality. Panels <b>A</b>, <b>C</b>, <b>E</b> and <b>G</b> plot <i>chico</i> heterozygotes <i>ch</i>^<i>+/-</i> relative to wildtype, <i>d4eBP</i> null mutant and the double mutant <i>ch</i>^<i>+/-</i><i>d4eBP</i>. Panels <b>B</b>, <b>D</b>, <b>F</b> and <b>H</b> plot <i>chico</i> homozygotes <i>ch</i>^<i>-/-</i> relative to wildtype, <i>d4eBP</i> null mutant and the double mutant <i>ch</i>^<i>-/-</i><i>d4eBP</i>.</p

Life table and proportional hazard survival analysis statistics of adult Drosophila wildtype, <i>chico</i>, <i>d4eBP</i> and <i>chico d4eBP</i> genotypes.

<p>Independent replicate trials, sexes (males & once mated females) maintained as separate cohorts. Number: adults for combined cages of synchronous cohorts. Upper (UL) and lower (LL) 95% confidence intervals for median lifespan. Relative risk estimated from Cox proportional hazard analyses for each genotype (row) relative to <i>chico</i> genotype (column); probability > χ ² based on log-likelihood (***) for p < 0.0001. Relative risk indicates fold change of the row genotype relative to the column <i>chico</i> genotype. Relative risk less than one (significant estimates in italics) indicate reduced mortality relative to the column <i>chico</i> genotype. Relative risk greater than one (significant estimates underlined) indicates increased mortality relative to the column <i>chico</i> genotype.</p

Activin Signaling Targeted by Insulin/dFOXO Regulates Aging and Muscle Proteostasis in <i>Drosophila</i>

<div><p>Reduced insulin/IGF signaling increases lifespan in many animals. To understand how insulin/IGF mediates lifespan in <i>Drosophila</i>, we performed chromatin immunoprecipitation-sequencing analysis with the insulin/IGF regulated transcription factor dFOXO in long-lived insulin/IGF signaling genotypes. Dawdle, an Activin ligand, is bound and repressed by dFOXO when reduced insulin/IGF extends lifespan. Reduced Activin signaling improves performance and protein homeostasis in muscles of aged flies. Activin signaling through the Smad binding element inhibits the transcription of <i>Autophagy-specific gene 8a (Atg8a)</i> within muscle, a factor controlling the rate of autophagy. Expression of <i>Atg8a</i> within muscle is sufficient to increase lifespan. These data reveal how insulin signaling can regulate aging through control of Activin signaling that in turn controls autophagy, representing a potentially conserved molecular basis for longevity assurance. While reduced Activin within muscle autonomously retards functional aging of this tissue, these effects in muscle also reduce secretion of insulin-like peptides at a distance from the brain. Reduced insulin secretion from the brain may subsequently reinforce longevity assurance through decreased systemic insulin/IGF signaling.</p></div

Proportional hazard analysis for survival during paraquat exposure and starvation.

<p>Proportional hazard modeled for <i>ch</i>^<i>+/-</i> and <i>d4eBP</i> as single and double mutants relative to wildtype, and <i>ch</i>^<i>-/-</i> and <i>d4eBP</i> as single and double mutants, with likelihood ratio test. Coefficient <i>β</i> for single loci: when significantly less than zero indicates reduction in mortality, estimates greater than zero indicate elevated mortality. Double mutants: coefficient <i>β</i> when significantly different from zero indicates gene interaction where the effect of the double mutant differs from expectation from product of single mutants. Epistasis inferred when significant gene interaction increases mortality (positive <i>β</i>) relative to expected product of <i>chico</i> and <i>d4eBP</i>; synergy inferred when gene interaction reduces mortality (negative <i>β</i>) relative to product of <i>chico</i> and <i>d4eBP</i> genotypes. Female and male survivorship when exposed to paraquat. Female and male survivorship during fasting.</p

Abundance of AKT, pAKT, 4E-BP and p4E-BP in whole adults of each <i>chico</i> genotype.

<p><b>A)</b> and <b>C)</b> Western blots with actin loading control. <b>B)</b> and <b>D)</b> Means (s.e.) from quantified replicate blots (n = 3) relative to actin within each matched sample. Significant differences (ANOVA, post hoc test) indicated by brace-lines: p < 0.05.</p

Inactivation of genes in Activin signaling (<i>daw</i>, <i>Smox</i> and <i>babo</i>) in muscle, but not in fat body extended lifespan.

<p>(A) Tissue-specific gene expression pattern of <i>daw</i>. (B) Tissue-specific distribution of transcription factor Smox using 7-day-old <i>Oregon R</i> females. (C–E) Lifespan analysis of Activin signaling using muscle-specific Gal4 driver (MHC-Gal4). Lifespan was extended by inactivating Activin genes (<i>daw</i>, <i>Smox</i> and <i>babo</i>) in muscle (Log-rank test, <i>p</i><0.0001). (F–H) Lifespan analysis of Activin signaling using adult fat body-specific Gal4 driver (S106-GS-Gal4). Fat body-specific inactivation of Activin genes (<i>daw</i> and <i>Smox</i>) shortens lifespan (Log-rank test, <i>p</i><0.0001). See <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003941#pgen.1003941.s012" target="_blank">Table S4</a> for survival analysis. (I, J) mRNA expression of <i>daw</i> and phosphorylation of Smox are down-regulated by <i>chico</i> mutation and rescued by mutation of dFOXO. Muscle and fat body were dissected from 7-day-old female wildtype, <i>chico^−/−</i> and <i>chico;foxo</i> double mutants. Band intensity was quantified using Bio-Rad Image Lab software. The average band intensity from four independent experiments is shown. Asterisk indicates significant difference between treatment and control (<i>p</i><0.05).</p