Ignition and chemical kinetics of acrolein-oxygen-argon mixtures behind reflected shock waves

In order to address increasing greenhouse gas emissions, the future fossil fuel shortage and increasingly stringent pollutant emission regulations, a variety of biofuels are being progressively incorporated into conventional transportation fuels. Despite the beneficial impact of biofuels on most regulated pollutants, their combustion induces the increase of a variety of aldehydes that are being considered for specific regulations due to their high toxicity. One of the most hazardous aldehyde compounds is acrolein, C_2H_3CHO. Despite its high toxicity and increased formation during bioalcohol and biodiesel combustion, no experimental data are available for acrolein combustion. In the present study, we have investigated the ignition of acrolein–oxygen–argon mixtures behind reflected shock wave using three simultaneous emission diagnostics monitoring OH∗, CH∗ and CO_2∗. Experiments were performed over a range of conditions: Φ = 0.5–2; T_5 = 1178–1602 K; and P_5 = 173–416 kPa. A tentative detailed reaction model, which includes sub-mechanisms for the three measured excited species, was developed to describe the high-temperature chemical kinetics of acrolein oxidation. Reasonable agreement was found between the model prediction and experimental data

Unresolved orthology and peculiar coding sequence properties of lamprey genes: the KCNA gene family as test case

Background:In understanding the evolutionary process of vertebrates, cyclostomes (hagfishes and lamprey) occupy crucial positions. Resolving molecular phylogenetic relationships of cyclostome genes with gnathostomes (jawed vertebrates) genes is indispensable in deciphering both the species tree and gene trees. However, molecular phylogenetic analyses, especially those including lamprey genes, have produced highly discordant results between gene families. To efficiently scrutinize this problem using partial genome assemblies of early vertebrates, we focused on the potassium voltage-gated channel, shaker-related (KCNA) family, whose members are mostly single-exon.Results:Seven sea lamprey KCNA genes as well as six elephant shark genes were identified, and their orthologies to bony vertebrate subgroups were assessed. In contrast to robustly supported orthology of the elephant shark genes to gnathostome subgroups, clear orthology of any sea lamprey gene could not be established. Notably, sea lamprey KCNA sequences displayed unique codon usage pattern and amino acid composition, probably associated with exceptionally high GC-content in their coding regions. This lamprey-specific property of coding sequences was also observed generally for genes outside this gene family.Conclusions:Our results suggest that secondary modifications of sequence properties unique to the lamprey lineage may be one of the factors preventing robust orthology assessments of lamprey genes, which deserves further genome-wide validation. The lamprey lineage-specific alteration of protein-coding sequence properties needs to be taken into consideration in tackling the key questions about early vertebrate evolution

Pyrolysis Gas Composition for a Phenolic Impregnated Carbon Ablator Heatshield

Published physical properties of phenolic impregnated carbon ablator (PICA) are compiled, and the composition of the pyrolysis gases that form at high temperatures internal to a heatshield is investigated. A link between the composition of the solid resin, and the composition of the pyrolysis gases created is provided. This link, combined with a detailed investigation into a reacting pyrolysis gas mixture, allows a consistent, and thorough description of many of the physical phenomena occurring in a PICA heatshield, and their implications, to be presented

Selective Estrogen Receptor Down-Regulator and Selective Estrogen Receptor Modulators Differentially Regulate Lactotroph Proliferation

occupation, differentially modulates the biological outcome of anti-estrogens. expression and release, as well as ERE-mediated transcriptional activity. expression

A Gene in the Process of Endosymbiotic Transfer

BACKGROUND: The endosymbiotic birth of organelles is accompanied by massive transfer of endosymbiont genes to the eukaryotic host nucleus. In the centric diatom Thalassiosira pseudonana the Psb28 protein is encoded in the plastid genome while a second version is nuclear-encoded and possesses a bipartite N-terminal presequence necessary to target the protein into the diatom complex plastid. Thus it can represent a gene captured during endosymbiotic gene transfer. METHODOLOGY/PRINCIPAL FINDINGS: To specify the origin of nuclear- and plastid-encoded Psb28 in T. pseudonana we have performed extensive phylogenetic analyses of both mentioned genes. We have also experimentally tested the intracellular location of the nuclear-encoded Psb28 protein (nuPsb28) through transformation of the diatom Phaeodactylum tricornutum with the gene in question fused to EYFP. CONCLUSIONS/SIGNIFICANCE: We show here that both versions of the psb28 gene in T. pseudonana are transcribed. We also provide experimental evidence for successful targeting of the nuPsb28 fused with EYFP to the diatom complex plastid. Extensive phylogenetic analyses demonstrate that nucleotide composition of the analyzed genes deeply influences the tree topology and that appropriate methods designed to deal with a compositional bias of the sequences and the long branch attraction artefact (LBA) need to be used to overcome this obstacle. We propose that nuclear psb28 in T. pseudonana is a duplicate of a plastid localized version, and that it has been transferred from its endosymbiont